2.0.0 release

* unifying Android and Desktop SDK

* implement desktop SDK adapter

* updating declarations

* change include syntax

* following jitpack.io guide for Android libraries

* add install task to all artefacts, add javadoc generation

* fixing javadoc

* use explicit provider "SC" instead of relying on order

* move to BouncyCastle for desktop compatibility

* improve documentation

.gitignore

@@ -1,9 +1,7 @@
 *.iml
 .gradle
 /local.properties
-/.idea/libraries
-/.idea/modules.xml
-/.idea/workspace.xml
+.idea
 .DS_Store
 /build
 /captures

README.md

@@ -0,0 +1,28 @@
+# Keycard Java SDK for Android and Desktop
+
+This SDK simplifies integration with the [Status Keycard](https://github.com/status-im/status-keycard) in Android
+and Desktop applications. In this SDK you find both the classes needed for generic communication with SmartCards as well 
+as classes specifically addressing the Keycard.
+
+To get started, check the file ```demo-android/src/main/java/im/status/keycard/app/MainActivity.java``` which a simple
+demo application showing how the SDK works and what you can do with it.
+
+## Usage
+
+You can import the SDK in your Gradle or Maven project using [Jitpack.io](https://jitpack.io).
+
+### On Android
+
+```groovy
+dependencies {
+  implementation 'com.github.status-im.status-keycard-java:android:2.0.0'
+}
+```
+
+### on the desktop
+
+```groovy
+dependencies {
+  implementation 'com.github.status-im.status-keycard-java:desktop:2.0.0'
+}
+```

android/.gitignore

@@ -0,0 +1,8 @@
+*.iml
+.gradle
+/local.properties
+.idea
+.DS_Store
+/build
+/captures
+.externalNativeBuild

android/build.gradle

@@ -0,0 +1,50 @@
+apply plugin: 'com.android.library'
+apply plugin: 'com.github.dcendents.android-maven'
+
+group = 'com.github.status-im'
+
+android {
+    compileSdkVersion 28
+    defaultConfig {
+        minSdkVersion 19
+        targetSdkVersion 28
+        versionCode 2
+        versionName "2.0"
+    }
+}
+
+dependencies {
+    api project(':lib')
+}
+
+// build a jar with source files
+task sourcesJar(type: Jar) {
+    from android.sourceSets.main.java.srcDirs
+    classifier = 'sources'
+}
+
+task javadoc(type: Javadoc) {
+    failOnError  false
+    source = android.sourceSets.main.java.sourceFiles
+    classpath += project.files(android.getBootClasspath().join(File.pathSeparator))
+    classpath += configurations.compile
+}
+
+// build a jar with javadoc
+task javadocJar(type: Jar, dependsOn: javadoc) {
+    classifier = 'javadoc'
+    from javadoc.destinationDir
+}
+
+artifacts {
+    archives sourcesJar
+    archives javadocJar
+}
+
+android.libraryVariants.all { variant ->
+    def name = variant.buildType.name
+    def task = project.tasks.create "jar${name.capitalize()}", Jar
+    task.dependsOn variant.javaCompile
+    task.from variant.javaCompile.destinationDir
+    artifacts.add('archives', task);
+}

android/src/main/AndroidManifest.xml

@@ -1,8 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-          package="im.status.hardwallet_lite_android">
+          package="im.status.keycard">
 
     <uses-permission android:name="android.permission.NFC" />
+    <uses-permission android:name="android.permission.INTERNET" />
     <uses-feature android:name="android.hardware.nfc.hce" android:required="true" />
 
 </manifest>

android/src/main/java/im/status/keycard/android/NFCCardChannel.java

@@ -0,0 +1,37 @@
+package im.status.keycard.android;
+
+import android.nfc.tech.IsoDep;
+import android.util.Log;
+import im.status.keycard.io.APDUCommand;
+import im.status.keycard.io.APDUResponse;
+import im.status.keycard.io.CardChannel;
+
+import java.io.IOException;
+
+/**
+ * Implementation of the CardChannel interface using the Android NFC API.
+ */
+public class NFCCardChannel implements CardChannel {
+  private static final String TAG = "CardChannel";
+
+  private IsoDep isoDep;
+
+  public NFCCardChannel(IsoDep isoDep) {
+    this.isoDep = isoDep;
+  }
+
+  @Override
+  public APDUResponse send(APDUCommand cmd) throws IOException {
+    byte[] apdu = cmd.serialize();
+    Log.d(TAG, String.format("COMMAND CLA: %02X INS: %02X P1: %02X P2: %02X LC: %02X", cmd.getCla(), cmd.getIns(), cmd.getP1(), cmd.getP2(), cmd.getData().length));
+    byte[] resp = this.isoDep.transceive(apdu);
+    APDUResponse response = new APDUResponse(resp);
+    Log.d(TAG, String.format("RESPONSE LEN: %02X, SW: %04X %n-----------------------", response.getData().length, response.getSw()));
+    return response;
+  }
+
+  @Override
+  public boolean isConnected() {
+    return this.isoDep.isConnected();
+  }
+}

android/src/main/java/im/status/keycard/android/NFCCardManager.java

@@ -0,0 +1,121 @@
+package im.status.keycard.android;
+
+import android.nfc.NfcAdapter;
+import android.nfc.Tag;
+import android.nfc.tech.IsoDep;
+import android.os.SystemClock;
+import android.util.Log;
+import im.status.keycard.globalplatform.Crypto;
+import im.status.keycard.io.CardListener;
+
+import java.io.IOException;
+
+/**
+ * Manages connection of NFC-based cards. Extends Thread and must be started using the start() method. The thread has
+ * a runloop which monitors the connection and from which CardListener callbacks are called.
+ */
+public class NFCCardManager extends Thread implements NfcAdapter.ReaderCallback {
+  private static final String TAG = "NFCCardManager";
+  private static final int DEFAULT_LOOP_SLEEP_MS = 50;
+
+  private IsoDep isoDep;
+  private boolean isRunning;
+  private CardListener cardListener;
+  private int loopSleepMS;
+
+  static {
+    Crypto.addSpongyCastleProvider();
+  }
+
+  /**
+   * Constructs an NFC Card Manager with default delay between loop iterations.
+   */
+  public NFCCardManager() {
+    this(DEFAULT_LOOP_SLEEP_MS);
+  }
+
+  /**
+   * Constructs an NFC Card Manager with the given delay between loop iterations.
+   *
+   * @param loopSleepMS time to sleep between loops
+   */
+  public NFCCardManager(int loopSleepMS) {
+    this.loopSleepMS = loopSleepMS;
+  }
+
+  /**
+   * True if connected, false otherwise.
+   * @return if connected, false otherwise
+   */
+  public boolean isConnected() {
+    return isoDep != null && isoDep.isConnected();
+  }
+
+  @Override
+  public void onTagDiscovered(Tag tag) {
+    isoDep = IsoDep.get(tag);
+    try {
+      isoDep = IsoDep.get(tag);
+      isoDep.connect();
+      isoDep.setTimeout(120000);
+    } catch (IOException e) {
+      Log.e(TAG, "error connecting to tag");
+    }
+  }
+
+  /**
+   * Runloop. Do NOT invoke directly. Use start() instead.
+   */
+  public void run() {
+    boolean connected = isConnected();
+
+    while (true) {
+      boolean newConnected = isConnected();
+      if (newConnected != connected) {
+        connected = newConnected;
+        Log.i(TAG, "tag " + (connected ? "connected" : "disconnected"));
+
+        if (connected && !isRunning) {
+          onCardConnected();
+        } else {
+          onCardDisconnected();
+        }
+      }
+
+      SystemClock.sleep(loopSleepMS);
+    }
+  }
+
+  /**
+   * Reacts on card connected by calling the callback of the registered listener.
+   */
+  private void onCardConnected() {
+    isRunning = true;
+
+    if (cardListener != null) {
+      cardListener.onConnected(new NFCCardChannel(isoDep));
+    }
+
+    isRunning = false;
+  }
+
+  /**
+   * Reacts on card disconnected by calling the callback of the registered listener.
+   */
+  private void onCardDisconnected() {
+    isRunning = false;
+    isoDep = null;
+    if (cardListener != null) {
+      cardListener.onDisconnected();
+    }
+  }
+
+  /**
+   * Sets the card listener.
+   *
+   * @param listener the new listener
+   */
+  public void setCardListener(CardListener listener) {
+    cardListener = listener;
+  }
+}

build.gradle

@@ -8,10 +8,7 @@ buildscript {
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:3.2.1'
-        
-
-        // NOTE: Do not place your application dependencies here; they belong
-        // in the individual module build.gradle files
+        classpath 'com.github.dcendents:android-maven-gradle-plugin:2.1'
     }
 }
 

demo-android/build.gradle

@@ -3,11 +3,11 @@ apply plugin: 'com.android.application'
 android {
     compileSdkVersion 28
     defaultConfig {
-        applicationId "im.status.hardwallet_lite_android.demo"
+        applicationId "im.status.keycard.demo"
         minSdkVersion 19
         targetSdkVersion 28
-        versionCode 1
-        versionName "1.0"
+        versionCode 2
+        versionName "2.0"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
     }
     buildTypes {
@@ -21,8 +21,10 @@ android {
 dependencies {
     implementation 'com.android.support:appcompat-v7:28.0.0'
     implementation 'com.android.support.constraint:constraint-layout:1.1.3'
+    implementation 'com.madgag.spongycastle:core:1.58.0.0'
+    implementation 'com.madgag.spongycastle:prov:1.58.0.0'
 
-    implementation project(':lib')
+    implementation project(':android')
 
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'com.android.support.test:runner:1.0.2'

demo-android/src/main/AndroidManifest.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-          package="im.status.hardwallet_lite_android.demo">
+          package="im.status.keycard.demo">
 
     <application
             android:allowBackup="true"
@@ -9,7 +9,7 @@
             android:roundIcon="@mipmap/ic_launcher_round"
             android:supportsRtl="true"
             android:theme="@style/AppTheme">
-        <activity android:name="im.status.hardwallet_lite_android.app.MainActivity">
+        <activity android:name="im.status.keycard.app.MainActivity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN"/>
 

demo-android/src/main/java/im/status/keycard/app/MainActivity.java

@@ -0,0 +1,167 @@
+package im.status.keycard.app;
+
+import android.nfc.NfcAdapter;
+import android.os.Bundle;
+import android.support.v7.app.AppCompatActivity;
+import android.util.Log;
+import im.status.keycard.demo.R;
+import im.status.keycard.io.CardChannel;
+import im.status.keycard.io.CardListener;
+import im.status.keycard.android.NFCCardManager;
+import im.status.keycard.applet.*;
+import org.spongycastle.util.encoders.Hex;
+
+public class MainActivity extends AppCompatActivity {
+
+  private static final String TAG = "MainActivity";
+
+  private NfcAdapter nfcAdapter;
+  private NFCCardManager cardManager;
+
+  @Override
+  protected void onCreate(Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+    setContentView(R.layout.activity_main);
+    nfcAdapter = NfcAdapter.getDefaultAdapter(this);
+    cardManager = new NFCCardManager();
+
+    cardManager.setCardListener(new CardListener() {
+      @Override
+      public void onConnected(CardChannel cardChannel) {
+        try {
+          // Applet-specific code
+          KeycardCommandSet cmdSet = new KeycardCommandSet(cardChannel);
+
+          Log.i(TAG, "Applet selection successful");
+
+          // First thing to do is selecting the applet on the card.
+          ApplicationInfo info = new ApplicationInfo(cmdSet.select().checkOK().getData());
+
+          // If the card is not initialized, the INIT apdu must be sent. The actual PIN, PUK and pairing password values
+          // can be either generated or chosen by the user. Using fixed values is highly discouraged.
+          if (!info.isInitializedCard()) {
+            Log.i(TAG, "Initializing card with test secrets");
+            cmdSet.init("000000", "123456789012", "KeycardTest").checkOK();
+            info = new ApplicationInfo(cmdSet.select().checkOK().getData());
+          }
+
+          Log.i(TAG, "Instance UID: " + Hex.toHexString(info.getInstanceUID()));
+          Log.i(TAG, "Secure channel public key: " + Hex.toHexString(info.getSecureChannelPubKey()));
+          Log.i(TAG, "Application version: " + info.getAppVersionString());
+          Log.i(TAG, "Free pairing slots: " + info.getFreePairingSlots());
+          if (info.hasMasterKey()) {
+            Log.i(TAG, "Key UID: " + Hex.toHexString(info.getKeyUID()));
+          } else {
+            Log.i(TAG, "The card has no master key");
+          }
+
+          // In real projects, the pairing key should be saved and used for all new sessions.
+          cmdSet.autoPair("KeycardTest");
+          Pairing pairing = cmdSet.getPairing();
+
+          // Never log the pairing key in a real application!
+          Log.i(TAG, "Pairing with card is done.");
+          Log.i(TAG, "Pairing index: " + pairing.getPairingIndex());
+          Log.i(TAG, "Pairing key: " + Hex.toHexString(pairing.getPairingKey()));
+
+          // Opening a Secure Channel is needed for all other applet commands
+          cmdSet.autoOpenSecureChannel();
+
+          Log.i(TAG, "Secure channel opened. Getting applet status.");
+
+          // We send a GET STATUS command, which does not require PIN authentication
+          ApplicationStatus status = new ApplicationStatus(cmdSet.getStatus(KeycardCommandSet.GET_STATUS_P1_APPLICATION).checkOK().getData());
+
+          Log.i(TAG, "PIN retry counter: " + status.getPINRetryCount());
+          Log.i(TAG, "PUK retry counter: " + status.getPUKRetryCount());
+          Log.i(TAG, "Has master key: " + status.hasMasterKey());
+
+          // A mnemonic can be generated before PIN authentication. Generating a mnemonic does not create keys on the
+          // card. a subsequent loadKey step must be performed after PIN authentication. In this example we will only
+          // show how to convert the output of the card to a usable format but won't actually load the key
+          Mnemonic mnemonic = new Mnemonic(cmdSet.generateMnemonic(KeycardCommandSet.GENERATE_MNEMONIC_12_WORDS).checkOK().getData());
+
+          // We need to set a wordlist if we plan using this object to derive the binary seed. If we just need the word
+          // indexes we can skip this step and call mnemonic.getIndexes() instead.
+          mnemonic.fetchBIP39EnglishWordlist();
+
+          Log.i(TAG, "Generated mnemonic phrase: " + mnemonic.toMnemonicPhrase());
+          Log.i(TAG, "Binary seed: " + Hex.toHexString(mnemonic.toBinarySeed()));
+
+          // PIN authentication allows execution of privileged commands
+          cmdSet.verifyPIN("000000").checkOK();
+
+          Log.i(TAG, "Pin Verified.");
+
+          // If the card has no keys, we generate a new set. Keys can also be loaded on the card starting from a binary
+          // seed generated from a mnemonic phrase. In alternative, we could load the generated keypair as shown in the
+          // commented line of code.
+          if (!status.hasMasterKey()) {
+            cmdSet.generateKey();
+            //cmdSet.loadKey(mnemonic.toBIP32KeyPair());
+          }
+
+          // Get the current key path using GET STATUS
+          KeyPath currentPath = new KeyPath(cmdSet.getStatus(KeycardCommandSet.GET_STATUS_P1_KEY_PATH).checkOK().getData());
+          Log.i(TAG, "Current key path: " + currentPath);
+
+          if (!currentPath.toString().equals("m/44'/0'/0'/0/0")) {
+            // Key derivation is needed to select the desired key. The derived key remains current until a new derive
+            // command is sent (it is not lost on power loss).
+            cmdSet.deriveKey("m/44'/0'/0'/0/0").checkOK();
+            Log.i(TAG, "Derived m/44'/0'/0'/0/0");
+          }
+
+          // We retrieve the wallet public key
+          BIP32KeyPair walletPublicKey = BIP32KeyPair.fromTLV(cmdSet.exportCurrentKey(true).checkOK().getData());
+
+          Log.i(TAG, "Wallet public key: " + Hex.toHexString(walletPublicKey.getPublicKey()));
+          Log.i(TAG, "Wallet address: " + Hex.toHexString(walletPublicKey.toEthereumAddress()));
+
+          byte[] hash = "thiscouldbeahashintheorysoitisok".getBytes();
+
+          RecoverableSignature signature = new RecoverableSignature(hash, cmdSet.sign(hash).checkOK().getData());
+
+          Log.i(TAG, "Signed hash: " + Hex.toHexString(hash));
+          Log.i(TAG, "Recovery ID: " + signature.getRecId());
+          Log.i(TAG, "R: " + Hex.toHexString(signature.getR()));
+          Log.i(TAG, "S: " + Hex.toHexString(signature.getS()));
+
+          // Cleanup, in a real application you would not unpair and instead keep the pairing key for successive interactions.
+          // We also remove all other pairings so that we do not fill all slots with failing runs. Again in real application
+          // this would be a very bad idea to do.
+          cmdSet.unpairOthers();
+          cmdSet.autoUnpair();
+
+          Log.i(TAG, "Unpaired.");
+
+        } catch (Exception e) {
+          Log.e(TAG, e.getMessage());
+        }
+
+      }
+
+      @Override
+      public void onDisconnected() {
+        Log.i(TAG, "Card disconnected.");
+      }
+    });
+    cardManager.start();
+  }
+
+  @Override
+  public void onResume() {
+    super.onResume();
+    if (nfcAdapter != null) {
+      nfcAdapter.enableReaderMode(this, this.cardManager, NfcAdapter.FLAG_READER_NFC_A | NfcAdapter.FLAG_READER_SKIP_NDEF_CHECK, null);
+    }
+  }
+
+  @Override
+  public void onPause() {
+    super.onPause();
+    if (nfcAdapter != null) {
+      nfcAdapter.disableReaderMode(this);
+    }
+  }
+}

demo-android/src/main/res/layout/activity_main.xml

@@ -5,7 +5,7 @@
         xmlns:app="http://schemas.android.com/apk/res-auto"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
-        tools:context=".app.MainActivity">
+        tools:context="im.status.keycard.app.MainActivity">
 
     <TextView
             android:layout_width="wrap_content"

demo-android/src/main/res/values/strings.xml

@@ -0,0 +1,3 @@
+<resources>
+    <string name="app_name">KeycardAndroid</string>
+</resources>

demo/src/main/java/im/status/hardwallet_lite_android/app/MainActivity.java

@@ -1,95 +0,0 @@
-package im.status.hardwallet_lite_android.app;
-
-import android.nfc.NfcAdapter;
-import android.os.Bundle;
-import android.support.v7.app.AppCompatActivity;
-import android.util.Log;
-import im.status.hardwallet_lite_android.demo.R;
-import im.status.hardwallet_lite_android.io.APDUResponse;
-import im.status.hardwallet_lite_android.io.CardChannel;
-import im.status.hardwallet_lite_android.io.CardManager;
-import im.status.hardwallet_lite_android.io.OnCardConnectedListener;
-import im.status.hardwallet_lite_android.wallet.WalletAppletCommandSet;
-
-public class MainActivity extends AppCompatActivity {
-
-  private static final String TAG = "MainActivity";
-
-  private NfcAdapter nfcAdapter;
-  private CardManager cardManager;
-
-  @Override
-  protected void onCreate(Bundle savedInstanceState) {
-    super.onCreate(savedInstanceState);
-    setContentView(R.layout.activity_main);
-    nfcAdapter = NfcAdapter.getDefaultAdapter(this);
-    cardManager = new CardManager();
-
-    cardManager.setOnCardConnectedListener(new OnCardConnectedListener() {
-      @Override
-      public void onConnected(CardChannel cardChannel) {
-        try {
-
-          Log.i(TAG, "onCardConnected()");
-
-          // Applet-specific code
-          WalletAppletCommandSet cmdSet = new WalletAppletCommandSet(cardChannel);
-
-          // First thing to do is selecting the applet on the card.
-          cmdSet.select().checkOK();
-
-          Log.i(TAG, "Applet is installed on the connected card.");
-
-          // In real projects, the pairing key should be saved and used for all new sessions.
-          cmdSet.autoPair("WalletAppletTest");
-
-          Log.i(TAG, "Pairing with card is done.");
-
-          // Opening a Secure Channel is needed for all other applet commands
-          cmdSet.autoOpenSecureChannel();
-
-          Log.i(TAG, "Secure channel opened.");
-
-          // We send a GET STATUS command, which does not require PIN authentication
-          APDUResponse resp = cmdSet.getStatus(WalletAppletCommandSet.GET_STATUS_P1_APPLICATION).checkOK();
-
-          Log.i(TAG, "Got status (response length=" + resp.getData().length + ")." );
-
-          // PIN authentication allows execution of privileged commands
-          cmdSet.verifyPIN("000000").checkOK();
-
-          Log.i(TAG, "Pin Verified.");
-
-          // Cleanup, in a real application you would not unpair and instead keep the pairing key for successive interactions.
-          // We also remove all other pairings so that we do not fill all slots with failing runs. Again in real application
-          // this would be a very bad idea to do.
-          cmdSet.unpairOthers();
-          cmdSet.autoUnpair();
-
-          Log.i(TAG, "Unpaired.");
-
-        } catch (Exception e) {
-          Log.e(TAG, e.getMessage());
-        }
-
-      }
-    });
-    cardManager.start();
-  }
-
-  @Override
-  public void onResume() {
-    super.onResume();
-    if (nfcAdapter != null) {
-      nfcAdapter.enableReaderMode(this, this.cardManager, NfcAdapter.FLAG_READER_NFC_A | NfcAdapter.FLAG_READER_SKIP_NDEF_CHECK, null);
-    }
-  }
-
-  @Override
-  public void onPause() {
-    super.onPause();
-    if (nfcAdapter != null) {
-      nfcAdapter.disableReaderMode(this);
-    }
-  }
-}

demo/src/main/res/values/strings.xml

@@ -1,3 +0,0 @@
-<resources>
-    <string name="app_name">HardwalletLiteAndroid</string>
-</resources>

desktop/.gitignore

@@ -0,0 +1,8 @@
+*.iml
+.gradle
+/local.properties
+.idea
+.DS_Store
+/build
+/captures
+.externalNativeBuild

desktop/build.gradle

@@ -0,0 +1,21 @@
+apply plugin: 'java'
+apply plugin: 'maven'
+
+dependencies {
+    compile project(':lib')
+}
+
+task sourcesJar(type: Jar, dependsOn: classes) {
+    classifier = 'sources'
+    from sourceSets.main.allSource
+}
+
+task javadocJar(type: Jar, dependsOn: javadoc) {
+    classifier = 'javadoc'
+    from javadoc.destinationDir
+}
+
+artifacts {
+    archives sourcesJar
+    archives javadocJar
+}

desktop/src/main/java/im/status/keycard/desktop/PCSCCardChannel.java

@@ -0,0 +1,50 @@
+package im.status.keycard.desktop;
+
+import im.status.keycard.globalplatform.Crypto;
+import im.status.keycard.io.APDUCommand;
+import im.status.keycard.io.APDUResponse;
+import im.status.keycard.io.CardChannel;
+
+import javax.smartcardio.CardException;
+import javax.smartcardio.CommandAPDU;
+import javax.smartcardio.ResponseAPDU;
+import java.io.IOException;
+
+/**
+ * Implementation of a CardChannel using the Java Smartcard I/O API,
+ */
+public class PCSCCardChannel implements CardChannel {
+  static {
+    Crypto.addSpongyCastleProvider();
+  }
+
+  private javax.smartcardio.CardChannel cardChannel;
+
+  /**
+   * Constructor. Wraps a Java Smartcard I/O CardChannel.
+   * @param cardChannel the card channel to wrap.
+   */
+  public PCSCCardChannel(javax.smartcardio.CardChannel cardChannel) {
+    this.cardChannel = cardChannel;
+  }
+
+  @Override
+  public APDUResponse send(APDUCommand cmd) throws IOException {
+    CommandAPDU capdu = new CommandAPDU(cmd.getCla(), cmd.getIns(), cmd.getP1(), cmd.getP2(), cmd.getData(), cmd.getNeedsLE() ? 0x100 : 0x00);
+
+    ResponseAPDU rapdu;
+
+    try {
+      rapdu = cardChannel.transmit(capdu);
+    } catch (CardException e) {
+      throw new IOException(e);
+    }
+
+    return new APDUResponse(rapdu.getBytes());
+  }
+
+  @Override
+  public boolean isConnected() {
+    return true;
+  }
+}

lib/build.gradle

@@ -1,26 +1,21 @@
-apply plugin: 'com.android.library'
-
-android {
-    compileSdkVersion 28
-    defaultConfig {
-        minSdkVersion 19
-        targetSdkVersion 28
-        versionCode 1
-        versionName "1.0"
-    }
-
-    task androidSourcesJar(type: Jar) {
-        from android.sourceSets.main.java.source
-        classifier = 'sources'
-    }
-
-    artifacts {
-        archives androidSourcesJar
-    }
-
-}
+apply plugin: 'java'
+apply plugin: 'maven'
 
 dependencies {
-    implementation 'com.madgag.spongycastle:core:1.58.0.0'
-    implementation 'com.madgag.spongycastle:prov:1.58.0.0'
+    implementation 'org.bouncycastle:bcprov-jdk15on:1.60'
+}
+
+task sourcesJar(type: Jar, dependsOn: classes) {
+    classifier = 'sources'
+    from sourceSets.main.allSource
+}
+
+task javadocJar(type: Jar, dependsOn: javadoc) {
+    classifier = 'javadoc'
+    from javadoc.destinationDir
+}
+
+artifacts {
+    archives sourcesJar
+    archives javadocJar
 }

lib/src/main/java/im/status/hardwallet_lite_android/io/APDUCommand.java

@@ -1,67 +0,0 @@
-package im.status.hardwallet_lite_android.io;
-
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-
-public class APDUCommand {
-    protected int cla;
-    protected int ins;
-    protected int p1;
-    protected int p2;
-    protected int lc;
-    protected byte[] data;
-    protected boolean needsLE;
-
-    public APDUCommand(int cla, int ins, int p1, int p2, byte[] data) {
-        this(cla, ins, p1, p2, data, false);
-    }
-
-    public APDUCommand(int cla, int ins, int p1, int p2, byte[] data, boolean needsLE) {
-        this.cla = cla;
-        this.ins = ins;
-        this.p1 = p1;
-        this.p2 = p2;
-        this.data = data;
-        this.needsLE = needsLE;
-    }
-
-    public byte[] serialize() throws IOException {
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
-        out.write(this.cla);
-        out.write(this.ins);
-        out.write(this.p1);
-        out.write(this.p2);
-        out.write(this.data.length);
-        out.write(this.data);
-
-        if (this.needsLE) {
-            out.write(0); // Response length
-        }
-
-        return out.toByteArray();
-    }
-
-    public int getCla() {
-        return cla;
-    }
-
-    public int getIns() {
-        return ins;
-    }
-
-    public int getP1() {
-        return p1;
-    }
-
-    public int getP2() {
-        return p2;
-    }
-
-    public byte[] getData() {
-        return data;
-    }
-
-    public boolean getNeedsLE() {
-        return this.needsLE;
-    }
-}

lib/src/main/java/im/status/hardwallet_lite_android/io/APDUException.java

@@ -1,15 +0,0 @@
-package im.status.hardwallet_lite_android.io;
-
-public class APDUException extends Exception {
-    public final int sw;
-
-    public APDUException(int sw, String message) {
-        super(message + ", 0x" + String.format("%04X", sw));
-        this.sw = sw;
-    }
-
-    public APDUException(String message) {
-        super(message);
-        this.sw = 0;
-    }
-}

lib/src/main/java/im/status/hardwallet_lite_android/io/APDUResponse.java

@@ -1,67 +0,0 @@
-package im.status.hardwallet_lite_android.io;
-
-public class APDUResponse {
-    public static int SW_OK = 0x9000;
-    public static int SW_SECURITY_CONDITION_NOT_SATISFIED = 0x6982;
-    public static int SW_AUTHENTICATION_METHOD_BLOCKED = 0x6983;
-    public static int SW_CARD_LOCKED = 0x6283;
-    public static int SW_REFERENCED_DATA_NOT_FOUND = 0x6A88;
-    public static int SW_CONDITIONS_OF_USE_NOT_SATISFIED = 0x6985; // applet may be already installed
-
-    private byte[] apdu;
-    private byte[] data;
-    private int sw;
-    private int sw1;
-    private int sw2;
-
-    public APDUResponse(byte[] apdu)  {
-        if (apdu.length < 2) {
-            throw new IllegalArgumentException("APDU response must be at least 2 bytes");
-        }
-        this.apdu = apdu;
-        this.parse();
-    }
-
-    private void parse() {
-        int length = this.apdu.length;
-
-        this.sw1 = this.apdu[length - 2] & 0xff;
-        this.sw2 = this.apdu[length - 1] & 0xff;
-        this.sw = (this.sw1 << 8) | this.sw2;
-
-        this.data = new byte[length - 2];
-        System.arraycopy(this.apdu, 0, this.data, 0, length - 2);
-    }
-
-    public boolean isOK() {
-        return this.sw == SW_OK;
-    }
-
-    public APDUResponse checkOK() throws APDUException {
-        if (!isOK()) {
-            throw new APDUException(this.getSw(),  "Unexpected error SW");
-        }
-
-        return this;
-    }
-
-    public byte[] getData() {
-        return this.data;
-    }
-
-    public int getSw() {
-        return this.sw;
-    }
-
-    public int getSw1() {
-        return this.sw1;
-    }
-
-    public int getSw2() {
-        return this.sw2;
-    }
-
-    public byte[] getBytes() {
-        return this.apdu;
-    }
-}

lib/src/main/java/im/status/hardwallet_lite_android/io/CardChannel.java

@@ -1,25 +0,0 @@
-package im.status.hardwallet_lite_android.io;
-
-import android.nfc.tech.IsoDep;
-import android.util.Log;
-import org.spongycastle.util.encoders.Hex;
-
-import java.io.IOException;
-
-public class CardChannel {
-    private static final String TAG = "CardChannel";
-
-    private IsoDep isoDep;
-
-    public CardChannel(IsoDep isoDep) {
-        this.isoDep = isoDep;
-    }
-
-    public APDUResponse send(APDUCommand cmd) throws IOException {
-        byte[] apdu = cmd.serialize();
-        Log.d(TAG, String.format("COMMAND  %s", Hex.toHexString(apdu)));
-        byte[] resp = this.isoDep.transceive(apdu);
-        Log.d(TAG, String.format("RESPONSE %s %n-----------------------", Hex.toHexString(resp)));
-        return new APDUResponse(resp);
-    }
-}

lib/src/main/java/im/status/hardwallet_lite_android/io/CardManager.java

@@ -1,76 +0,0 @@
-package im.status.hardwallet_lite_android.io;
-
-import android.nfc.NfcAdapter;
-import android.nfc.Tag;
-import android.nfc.tech.IsoDep;
-import android.os.SystemClock;
-import android.util.Log;
-import java.io.IOException;
-import java.security.Security;
-
-public class CardManager extends Thread implements NfcAdapter.ReaderCallback {
-
-    public CardManager() {
-        Security.insertProviderAt(new org.spongycastle.jce.provider.BouncyCastleProvider(), 1);
-    }
-
-    private static final String TAG = "CardManager";
-
-    private IsoDep isoDep;
-    private boolean isRunning;
-    private OnCardConnectedListener onCardConnectedListener;
-
-    public boolean isConnected() {
-        return isoDep != null && isoDep.isConnected();
-    }
-
-    @Override
-    public void onTagDiscovered(Tag tag) {
-        isoDep = IsoDep.get(tag);
-
-        try {
-            isoDep = IsoDep.get(tag);
-            isoDep.connect();
-            isoDep.setTimeout(120000);
-        } catch (IOException e) {
-            Log.e(TAG, "error connecting to tag");
-        }
-    }
-
-    public void run() {
-        boolean connected = isConnected();
-
-        while (true) {
-            boolean newConnected = isConnected();
-            if (newConnected != connected) {
-                connected = newConnected;
-                Log.i(TAG, "tag " + (connected ? "connected" : "disconnected"));
-
-                if (connected && !isRunning) {
-                    onCardConnected();
-                } else {
-                    onCardDisconnected();
-                }
-            }
-
-            SystemClock.sleep(50);
-        }
-    }
-
-    private void onCardConnected() {
-        isRunning = true;
-
-        onCardConnectedListener.onConnected(new CardChannel(isoDep));
-
-        isRunning = false;
-    }
-
-    private void onCardDisconnected() {
-        isRunning = false;
-        isoDep = null;
-    }
-
-    public void setOnCardConnectedListener(OnCardConnectedListener onConnectedListener) {
-        onCardConnectedListener = onConnectedListener;
-    }
-}

lib/src/main/java/im/status/hardwallet_lite_android/io/OnCardConnectedListener.java

@@ -1,5 +0,0 @@
-package im.status.hardwallet_lite_android.io;
-
-public interface OnCardConnectedListener {
-    void onConnected(CardChannel channel);
-}

lib/src/main/java/im/status/keycard/applet/ApplicationInfo.java

@@ -0,0 +1,118 @@
+package im.status.keycard.applet;
+
+/**
+ * Parses the response from a SELECT command. If the card has not yet received the INIT command the isInitializedCard
+ * will return false and only the getSecureChannelPubKey method will return a valid value.
+ */
+public class ApplicationInfo {
+  private boolean initializedCard;
+  private byte[] instanceUID;
+  private byte[] secureChannelPubKey;
+  private short appVersion;
+  private byte freePairingSlots;
+  private byte[] keyUID;
+
+  public static final byte TLV_APPLICATION_INFO_TEMPLATE = (byte) 0xA4;
+  public static final byte TLV_PUB_KEY = (byte) 0x80;
+  public static final byte TLV_UID = (byte) 0x8F;
+  public static final byte TLV_KEY_UID = (byte) 0x8E;
+
+  /**
+   * Constructs an object by parsing the TLV data.
+   *
+   * @param tlvData the raw response data from the card
+   * @throws IllegalArgumentException the TLV does not follow the allowed format
+   */
+  public ApplicationInfo(byte[] tlvData) throws IllegalArgumentException {
+    TinyBERTLV tlv = new TinyBERTLV(tlvData);
+
+    int topTag = tlv.readTag();
+    tlv.unreadLastTag();
+
+    if (topTag == TLV_PUB_KEY) {
+      secureChannelPubKey = tlv.readPrimitive(TLV_PUB_KEY);
+      initializedCard = false;
+      return;
+    }
+
+    tlv.enterConstructed(TLV_APPLICATION_INFO_TEMPLATE);
+    instanceUID = tlv.readPrimitive(TLV_UID);
+    secureChannelPubKey = tlv.readPrimitive(TLV_PUB_KEY);
+    appVersion = (short) tlv.readInt();
+    freePairingSlots = (byte) tlv.readInt();
+    keyUID = tlv.readPrimitive(TLV_KEY_UID);
+    initializedCard = true;
+  }
+
+  /**
+   * Returns if the card is initialized or not. If this method returns false, only the getSecureChannelPubKey method
+   * will return a valid value.
+   *
+   * @return true if initialized, false otherwise
+   */
+  public boolean isInitializedCard() {
+    return initializedCard;
+  }
+
+  /**
+   * Utility method to discover if the card has a master key.
+   *
+   * @return true if the card has a master key, false otherwise
+   */
+  public boolean hasMasterKey() {
+    return keyUID.length != 0;
+  }
+
+  /**
+   * The instance UID of the applet. This ID never changes for the lifetime of the applet.
+   *
+   * @return the instance UID
+   */
+  public byte[] getInstanceUID() {
+    return instanceUID;
+  }
+
+  /**
+   * The public key to be used for secure channel opening. Usually handled internally by the KeycardCommandSet.
+   *
+   * @return the public key
+   */
+  public byte[] getSecureChannelPubKey() {
+    return secureChannelPubKey;
+  }
+
+  /**
+   * The application version, encoded as a short. The msb is the major revision number and the lsb is the minor one.
+   *
+   * @return the application version
+   */
+  public short getAppVersion() {
+    return appVersion;
+  }
+
+  /**
+   * A formatted application version.
+   * @return the string representation of the application version
+   */
+  public String getAppVersionString() {
+    return (appVersion >> 8) + "." + (appVersion & 0xff);
+  }
+
+  /**
+   * The number of remaining pairing slots. If zero is returned, no further pairing is possible.
+   * @return the number of remaining pairing slots
+   */
+  public byte getFreePairingSlots() {
+    return freePairingSlots;
+  }
+
+  /**
+   * The UID of the master key on this card. Changes every time a different master key is stored. It has zero length if
+   * no key is on the card.
+   *
+   * @return the Key UID.
+   */
+  public byte[] getKeyUID() {
+    return keyUID;
+  }
+}

lib/src/main/java/im/status/keycard/applet/ApplicationStatus.java

@@ -0,0 +1,50 @@
+package im.status.keycard.applet;
+
+/**
+ * Parses the result of a GET STATUS command retrieving application status.
+ */
+public class ApplicationStatus {
+  private byte pinRetryCount;
+  private byte pukRetryCount;
+  private boolean hasMasterKey;
+
+  public static final byte TLV_APPLICATION_STATUS_TEMPLATE = (byte) 0xA3;
+
+  /**
+   * Constructor from TLV data
+   * @param tlvData the TLV data
+   * @throws IllegalArgumentException if the TLV does not follow the expected format
+   */
+  public ApplicationStatus(byte[] tlvData) throws IllegalArgumentException {
+    TinyBERTLV tlv = new TinyBERTLV(tlvData);
+    tlv.enterConstructed(TLV_APPLICATION_STATUS_TEMPLATE);
+    pinRetryCount = (byte) tlv.readInt();
+    pukRetryCount = (byte) tlv.readInt();
+    hasMasterKey = tlv.readBoolean();
+  }
+
+  /**
+   * The available PIN retry count.
+   * @return the available PIN retry count
+   */
+  public byte getPINRetryCount() {
+    return pinRetryCount;
+  }
+
+  /**
+   * The available PUK retry count.
+   * @return the available PUK retry count
+   */
+  public byte getPUKRetryCount() {
+    return pukRetryCount;
+  }
+
+  /**
+   * Whether the card has a master key or not.
+   *
+   * @return whether the card has a master key or not.
+   */
+  public boolean hasMasterKey() {
+    return hasMasterKey;
+  }
+}

lib/src/main/java/im/status/keycard/applet/BIP32KeyPair.java

@@ -0,0 +1,223 @@
+package im.status.keycard.applet;
+
+import org.bouncycastle.crypto.digests.KeccakDigest;
+import org.bouncycastle.math.ec.ECPoint;
+
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+import java.math.BigInteger;
+import java.util.Arrays;
+
+/**
+ * Represents a BIP32 keypair. This can be a master key or any other key in the path. Contains convenience method to
+ * read and write formats the the card understands.
+ */
+public class BIP32KeyPair {
+  private byte[] privateKey;
+  private byte[] chainCode;
+  private byte[] publicKey;
+
+  static final byte TLV_KEY_TEMPLATE = (byte) 0xA1;
+  static final byte TLV_PUB_KEY = (byte) 0x80;
+  static final byte TLV_PRIV_KEY = (byte) 0x81;
+  static final byte TLV_CHAIN_CODE = (byte) 0x82;
+
+  /**
+   * Returns a BIP32 keypair from a BIP32 binary seed. It includes all components.
+   *
+   * @param binarySeed the binary seed
+   * @return the BIP32 keypair
+   */
+  public static BIP32KeyPair fromBinarySeed(byte[] binarySeed) {
+    try {
+      Mac hmacSHA512 = Mac.getInstance("HmacSHA512");
+      SecretKeySpec keySpec = new SecretKeySpec("Bitcoin seed".getBytes(), "HmacSHA512");
+      hmacSHA512.init(keySpec);
+      byte[] mac = hmacSHA512.doFinal(binarySeed);
+      return new BIP32KeyPair(Arrays.copyOf(mac, 32), Arrays.copyOfRange(mac, 32, 64), null);
+    } catch (Exception e) {
+      throw new RuntimeException("Is BouncyCastle correctly installed? ", e);
+    }
+  }
+
+  /**
+   * Constructs a BIP32 keypair from a KEY TEMPLATE TLV. If the data is the output of the EXPORT KEY command, it will
+   * never contain the chain code field and could contain only the public key.
+   *
+   * @param tlvData the TLV data
+   * @return the BIP32 keypair
+   */
+  public static BIP32KeyPair fromTLV(byte[] tlvData) {
+    TinyBERTLV tlv = new TinyBERTLV(tlvData);
+    tlv.enterConstructed(TLV_KEY_TEMPLATE);
+
+    byte[] pubKey = null;
+    byte[] privKey = null;
+    byte[] chainCode = null;
+
+    int tag = tlv.readTag();
+
+    if (tag == TLV_PUB_KEY) {
+      tlv.unreadLastTag();
+      pubKey = tlv.readPrimitive(TLV_PUB_KEY);
+      tag = tlv.readTag();
+    }
+
+    if (tag == TLV_PRIV_KEY) {
+      tlv.unreadLastTag();
+      privKey = tlv.readPrimitive(TLV_PRIV_KEY);
+      tag = tlv.readTag();
+
+      if (tag == TLV_CHAIN_CODE) {
+        tlv.unreadLastTag();
+        chainCode = tlv.readPrimitive(TLV_CHAIN_CODE);
+      }
+    }
+
+    return new BIP32KeyPair(privKey, chainCode, pubKey);
+  }
+
+  /**
+   * Low level constructor. If the private key is not null, the public key can be omitted and it will be calculated
+   * automatically. If the private key is null the chain code must be null and the public key must be not null.
+   *
+   * @param privateKey the private key
+   * @param chainCode the chain code
+   * @param publicKey the public key
+   */
+  public BIP32KeyPair(byte[] privateKey, byte[] chainCode, byte[] publicKey) {
+    if (privateKey == null && (chainCode != null || publicKey == null))  {
+      throw new IllegalArgumentException("Private key can be null only if the public key is not null and the chain code is null");
+    }
+    
+    this.privateKey = privateKey;
+    this.chainCode = chainCode;
+    
+    if (publicKey != null) {
+      this.publicKey = publicKey;
+    } else {
+      calculatePublicKey();
+    }
+  }
+
+  private void calculatePublicKey() {
+    BigInteger k = new BigInteger(1, this.privateKey);
+    ECPoint pubKey = RecoverableSignature.CURVE.getG().multiply(k);
+    this.publicKey = pubKey.getEncoded(false);
+  }
+
+  /**
+   * Returns the TLV representation of this object.
+   *
+   * @return the TLV representation of this object.
+   */
+  public byte[] toTLV() {
+    return toTLV(true);
+  }
+
+  /**
+   * Returns the TLV representation of this object, optionally omitting the public component.
+   *
+   * @return the TLV representation of this object.
+   */
+  public byte[] toTLV(boolean includePublic) {
+    int privLen = privateKey.length;
+    int privOff = 0;
+
+    if(privateKey[0] == 0x00) {
+      privOff++;
+      privLen--;
+    }
+
+    int off = 0;
+    int totalLength = includePublic ? (publicKey.length + 2) : 0;
+    totalLength += (privLen + 2);
+    totalLength += isExtended() ? (chainCode.length + 2) : 0;
+
+    if (totalLength > 127) {
+      totalLength += 3;
+    } else {
+      totalLength += 2;
+    }
+
+    byte[] data = new byte[totalLength];
+    data[off++] = TLV_KEY_TEMPLATE;
+
+    if (totalLength > 127) {
+      data[off++] = (byte) 0x81;
+      data[off++] = (byte) (totalLength - 3);
+    } else {
+      data[off++] = (byte) (totalLength - 2);
+    }
+
+    if (includePublic) {
+      data[off++] = TLV_PUB_KEY;
+      data[off++] = (byte) publicKey.length;
+      System.arraycopy(publicKey, 0, data, off, publicKey.length);
+      off += publicKey.length;
+    }
+
+    data[off++] = TLV_PRIV_KEY;
+    data[off++] = (byte) privLen;
+    System.arraycopy(privateKey, privOff, data, off, privLen);
+    off += privLen;
+
+    if (isExtended()) {
+      data[off++] = (byte) TLV_CHAIN_CODE;
+      data[off++] = (byte) chainCode.length;
+      System.arraycopy(chainCode, 0, data, off, chainCode.length);
+    }
+
+    return data;
+  }
+
+  public byte[] toEthereumAddress() {
+    KeccakDigest digest = new KeccakDigest(256);
+    digest.update(publicKey, 1, (publicKey.length - 1));
+    byte[] hash = new byte[32];
+    digest.doFinal(hash, 0);
+    return Arrays.copyOfRange(hash,12, hash.length);
+  }
+
+  /**
+   * Returns the private key. Might be null.
+   *
+   * @return the private key
+   */
+  public byte[] getPrivateKey() {
+    return privateKey;
+  }
+
+  /**
+   * Returns the chain code. Might be null.
+   *
+   * @return the chain code
+   */
+  public byte[] getChainCode() {
+    return chainCode;
+  }
+
+  /**
+   * Returns the public key. Is never null.
+   * @return the public key
+   */
+  public byte[] getPublicKey() {
+    return publicKey;
+  }
+
+  /**
+   * True if only the public key is contained, false otherwise.
+   * @return true or false
+   */
+  public boolean isPublicOnly() {
+    return privateKey == null;
+  }
+
+  /**
+   * True if the chain code is contained, false otherwise.
+   * @return true or false
+   */
+  public boolean isExtended() {
+    return chainCode != null;
+  }
+}

lib/src/main/java/im/status/keycard/applet/CardDuplicator.java

@@ -0,0 +1,96 @@
+package im.status.keycard.applet;
+
+import im.status.keycard.io.APDUException;
+import im.status.keycard.io.CardChannel;
+
+import java.io.IOException;
+import java.security.SecureRandom;
+
+/**
+ * Class helping with the card duplication process. Depending on the device's role, only some of the methods are relevant.
+ *
+ * WORK IN PROGRESS, DO NOT USE YET
+ */
+public class CardDuplicator {
+  private byte[] secret;
+
+  /**
+   * Creates a CardDuplicator object. Regardless of the role of the device, this object must be kept and used for the
+   * entire duplication session. It cannot be reused for multiple sessions.
+   */
+  public CardDuplicator() {
+    secret = new byte[32];
+    SecureRandom random = new SecureRandom();
+    random.nextBytes(secret);
+  }
+
+  private KeycardCommandSet preamble(CardChannel channel, Pairing pairing, String pin) throws IOException, APDUException {
+    KeycardCommandSet cmdSet = new KeycardCommandSet(channel);
+    cmdSet.select().checkOK();
+    cmdSet.setPairing(pairing);
+    cmdSet.autoOpenSecureChannel();
+    cmdSet.verifyPIN(pin).checkOK();
+    return cmdSet;
+  }
+
+  /**
+   * Starts duplication session. Must be used on all cards taking part of in the duplication process.
+   *
+   * @param channel the card channel
+   * @param pairing the pairing info
+   * @param pin the card PIN
+   * @param deviceCount the number of devices which will be adding entropy for the key, including this one
+   *
+   * @throws IOException communication error
+   * @throws APDUException unexpected card response
+   */
+  public void startDuplication(CardChannel channel, Pairing pairing, String pin, int deviceCount) throws IOException, APDUException {
+    KeycardCommandSet cmdSet = preamble(channel, pairing, pin);
+    cmdSet.duplicateKeyStart(deviceCount, secret).checkOK();
+  }
+
+  /**
+   * Exports key. Must be used on the card designated as the source for the duplication.
+   *
+   * @param channel the card channel
+   * @param pairing the pairing info
+   * @param pin the card PIN
+   *
+   * @throws IOException communication error
+   * @throws APDUException unexpected card response
+   */
+  public byte[] exportKey(CardChannel channel, Pairing pairing, String pin) throws IOException, APDUException {
+    KeycardCommandSet cmdSet = preamble(channel, pairing, pin);
+    return cmdSet.duplicateKeyExport().checkOK().getData();
+  }
+
+  /**
+   * Imports key. Must be used on all cards designated as the target for the duplication.
+   * @param channel the card channel
+   * @param pairing the pairing info
+   * @param pin the user PIN
+   * @param key the key to import
+   * @return the key UID
+   * @throws IOException communication error
+   * @throws APDUException unexpected card response
+   */
+  public byte[] importKey(CardChannel channel, Pairing pairing, String pin, byte[] key) throws IOException, APDUException {
+    KeycardCommandSet cmdSet = preamble(channel, pairing, pin);
+    return cmdSet.duplicateKeyImport(key).checkOK().getData();
+  }
+
+  /**
+   * Adds entropy. Must be used on all cards taking part in the backup process. Each device taking part must use this
+   * exactly once, except for the device which started the backup.
+   *
+   * @param channel
+   * @throws IOException communication error
+   * @throws APDUException unexpected card response
+   */
+  public void addEntropy(CardChannel channel) throws IOException, APDUException {
+    KeycardCommandSet cmdSet = new KeycardCommandSet(channel);
+    cmdSet.select().checkOK();
+    cmdSet.duplicateKeyAddEntropy(secret).checkOK();
+  }
+
+}

lib/src/main/java/im/status/keycard/applet/Identifiers.java

@@ -0,0 +1,40 @@
+package im.status.keycard.applet;
+
+import org.bouncycastle.util.encoders.Hex;
+
+import java.util.Arrays;
+
+public class Identifiers {
+  public static final byte[] PACKAGE_AID = Hex.decode("A0000008040001");
+
+  public static final byte[] KEYCARD_AID = Hex.decode("A000000804000101");
+  public static final int KEYCARD_DEFAULT_INSTANCE_IDX = 1;
+
+  public static final byte[] NDEF_AID = Hex.decode("A000000804000102");
+  public static final byte[] NDEF_INSTANCE_AID = Hex.decode("D2760000850101");
+
+  /**
+   * Gets the instance AID of the default instance of the Keycard applet.
+   *
+   * @return the instance AID of the Keycard applet
+   */
+  public static byte[] getKeycardInstanceAID() {
+    return getKeycardInstanceAID(KEYCARD_DEFAULT_INSTANCE_IDX);
+  }
+
+  /**
+   * Gets the instance AID of the Keycard applet with the given index. Since multiple instances of the Keycard applet
+   * could be installed in parallel, this method allows selecting a specific instance. The index is between 01 and ff
+   *
+   * @return the instance AID of the Keycard applet
+   */
+  public static byte[] getKeycardInstanceAID(int instanceIdx) {
+    if (instanceIdx < 0x01 || instanceIdx > 0xff) {
+      throw new IllegalArgumentException("The instance index must be between 1 and 255");
+    }
+
+    byte[] instanceAID = Arrays.copyOf(KEYCARD_AID, KEYCARD_AID.length + 1);
+    instanceAID[KEYCARD_AID.length] = (byte) instanceIdx;
+    return instanceAID;
+  }
+}

lib/src/main/java/im/status/keycard/applet/KeyPath.java

@@ -0,0 +1,145 @@
+package im.status.keycard.applet;
+
+import java.util.StringTokenizer;
+
+/**
+ * Keypath object to be used with the KeycardCommandSet
+ */
+public class KeyPath {
+  private int source;
+  private byte[] data;
+
+  /**
+   * Parses a keypath into a byte array and source parameter to be used with the KeycardCommandSet object.
+   *
+   * A valid string is composed of a minimum of one and a maximum of 11 components separated by "/".
+   *
+   * The first component can be either "m", indicating the master key, "..", indicating the parent of the current key,
+   * or "." indicating the current key. It can also be omitted, in which case it is considered the same as being ".".
+   *
+   * All other components are positive integers fitting in 31 bit, eventually suffixed by an apostrophe (') sign,
+   * which indicates an hardened key.
+   *
+   * An example of a valid path is "m/44'/0'/0'/0/0"
+   *
+   *
+   * @param keypath the keypath as a string
+   */
+  public KeyPath(String keypath) {
+    StringTokenizer tokenizer = new StringTokenizer(keypath, "/");
+
+    String sourceOrFirstElement = tokenizer.nextToken();
+
+    switch(sourceOrFirstElement) {
+      case "m":
+        source = KeycardCommandSet.DERIVE_P1_SOURCE_MASTER;
+        break;
+      case "..":
+        source = KeycardCommandSet.DERIVE_P1_SOURCE_PARENT;
+        break;
+      case ".":
+        source = KeycardCommandSet.DERIVE_P1_SOURCE_CURRENT;
+        break;
+      default:
+        source = KeycardCommandSet.DERIVE_P1_SOURCE_CURRENT;
+        tokenizer = new StringTokenizer(keypath, "/"); // rewind
+        break;
+    }
+
+    int componentCount = tokenizer.countTokens();
+    if (componentCount > 10) {
+      throw new IllegalArgumentException("Too many components");
+    }
+
+    data = new byte[4 * componentCount];
+
+    for (int i = 0; i < componentCount; i++) {
+      long component = parseComponent(tokenizer.nextToken());
+      writeComponent(component, i);
+    }
+  }
+
+  public KeyPath(byte[] data, int source) {
+    this.data = data;
+    this.source = source;
+  }
+
+  public KeyPath(byte[] data) {
+    this(data, KeycardCommandSet.DERIVE_P1_SOURCE_MASTER);
+  }
+
+  private long parseComponent(String num) {
+    long sign;
+
+    if (num.endsWith("'")) {
+      sign = 0x80000000L;
+      num = num.substring(0, (num.length() - 1));
+    } else {
+      sign = 0L;
+    }
+
+    if (num.startsWith("+") || num.startsWith("-")) {
+      throw new NumberFormatException("No sign allowed");
+    }
+    return (sign | Long.parseLong(num));
+  }
+
+  private void writeComponent(long component, int i) {
+    int off = (i*4);
+    data[off] = (byte)((component >> 24) & 0xff);
+    data[off + 1] = (byte)((component >> 16) & 0xff);
+    data[off + 2] = (byte)((component >> 8) & 0xff);
+    data[off + 3] = (byte)(component & 0xff);
+  }
+
+  /**
+   * The source of the derive command.
+   *
+   * @return the source of the derive command
+   */
+  public int getSource() {
+    return source;
+  }
+
+  /**
+   * The byte encoded key path.
+   *
+   * @return byte encoded key path
+   */
+  public byte[] getData() {
+    return data;
+  }
+
+  @Override
+  public String toString() {
+    StringBuffer sb = new StringBuffer();
+
+    switch(source) {
+      case KeycardCommandSet.DERIVE_P1_SOURCE_MASTER:
+        sb.append('m');
+        break;
+      case KeycardCommandSet.DERIVE_P1_SOURCE_PARENT:
+        sb.append("..");
+        break;
+      case KeycardCommandSet.DERIVE_P1_SOURCE_CURRENT:
+        sb.append('.');
+        break;
+    }
+
+    for (int i = 0; i < this.data.length; i += 4) {
+      sb.append('/');
+      appendComponent(sb, i);
+    }
+
+    return sb.toString();
+  }
+
+  private void appendComponent(StringBuffer sb, int i) {
+    int num = ((this.data[i] & 0x7f) << 24) | ((this.data[i+1] & 0xff) << 16) | ((this.data[i+2] & 0xff) << 8) | (this.data[i+3] & 0xff);
+    sb.append(num);
+
+    if ((this.data[i] & 0x80) == 0x80) {
+      sb.append('\'');
+    }
+  }
+}

lib/src/main/java/im/status/keycard/applet/KeycardCommandSet.java

@@ -1,19 +1,17 @@
-package im.status.hardwallet_lite_android.wallet;
+package im.status.keycard.applet;
 
-import im.status.hardwallet_lite_android.io.APDUCommand;
-import im.status.hardwallet_lite_android.io.APDUException;
-import im.status.hardwallet_lite_android.io.APDUResponse;
-import im.status.hardwallet_lite_android.io.CardChannel;
-import org.spongycastle.jce.interfaces.ECPrivateKey;
-import org.spongycastle.jce.interfaces.ECPublicKey;
-import org.spongycastle.util.encoders.Hex;
+import im.status.keycard.io.APDUCommand;
+import im.status.keycard.io.APDUException;
+import im.status.keycard.io.APDUResponse;
+import im.status.keycard.io.CardChannel;
+import org.bouncycastle.jce.interfaces.ECPrivateKey;
+import org.bouncycastle.jce.interfaces.ECPublicKey;
 
 import javax.crypto.SecretKey;
 import javax.crypto.SecretKeyFactory;
 import javax.crypto.spec.PBEKeySpec;
 import java.io.IOException;
 import java.security.KeyPair;
-import java.security.PrivateKey;
 import java.util.Arrays;
 
 /**
@@ -21,9 +19,10 @@ import java.util.Arrays;
  * file. Some APDUs map to multiple methods for the sake of convenience since their payload or response require some
  * pre/post processing.
  */
-public class WalletAppletCommandSet {
+public class KeycardCommandSet {
   static final byte INS_INIT = (byte) 0xFE;
   static final byte INS_GET_STATUS = (byte) 0xF2;
+  static final byte INS_SET_NDEF = (byte) 0xF3;
   static final byte INS_VERIFY_PIN = (byte) 0x20;
   static final byte INS_CHANGE_PIN = (byte) 0x21;
   static final byte INS_UNBLOCK_PIN = (byte) 0x22;
@@ -31,65 +30,96 @@ public class WalletAppletCommandSet {
   static final byte INS_DERIVE_KEY = (byte) 0xD1;
   static final byte INS_GENERATE_MNEMONIC = (byte) 0xD2;
   static final byte INS_REMOVE_KEY = (byte) 0xD3;
+  static final byte INS_GENERATE_KEY = (byte) 0xD4;
+  static final byte INS_DUPLICATE_KEY = (byte) 0xD5;
   static final byte INS_SIGN = (byte) 0xC0;
   static final byte INS_SET_PINLESS_PATH = (byte) 0xC1;
   static final byte INS_EXPORT_KEY = (byte) 0xC2;
 
   public static final byte GET_STATUS_P1_APPLICATION = 0x00;
+  public static final byte GET_STATUS_P1_KEY_PATH = 0x01;
 
-  static final byte LOAD_KEY_P1_EC = 0x01;
-  static final byte LOAD_KEY_P1_EXT_EC = 0x02;
-  static final byte LOAD_KEY_P1_SEED = 0x03;
+  public static final byte LOAD_KEY_P1_EC = 0x01;
+  public static final byte LOAD_KEY_P1_EXT_EC = 0x02;
+  public static final byte LOAD_KEY_P1_SEED = 0x03;
 
-  static final byte DERIVE_P1_ASSISTED_MASK = 0x01;
-  static final byte DERIVE_P1_SOURCE_MASTER = (byte) 0x00;
+  public static final byte DERIVE_P1_SOURCE_MASTER = (byte) 0x00;
+  public static final byte DERIVE_P1_SOURCE_PARENT = (byte) 0x40;
+  public static final byte DERIVE_P1_SOURCE_CURRENT = (byte) 0x80;
 
-  static final byte DERIVE_P2_KEY_PATH = 0x00;
-  static final byte DERIVE_P2_PUBLIC_KEY = 0x01;
+  static final byte DUPLICATE_KEY_P1_START = 0x00;
+  static final byte DUPLICATE_KEY_P1_ADD_ENTROPY = 0x01;
+  static final byte DUPLICATE_KEY_P1_EXPORT = 0x02;
+  static final byte DUPLICATE_KEY_P1_IMPORT = 0x03;
+
+  public static final int GENERATE_MNEMONIC_12_WORDS = 0x04;
+  public static final int GENERATE_MNEMONIC_15_WORDS = 0x05;
+  public static final int GENERATE_MNEMONIC_18_WORDS = 0x06;
+  public static final int GENERATE_MNEMONIC_21_WORDS = 0x07;
+  public static final int GENERATE_MNEMONIC_24_WORDS = 0x08;
+
+  static final byte EXPORT_KEY_P1_CURRENT = 0x00;
+  static final byte EXPORT_KEY_P1_DERIVE = 0x01;
+  static final byte EXPORT_KEY_P1_DERIVE_AND_MAKE_CURRENT = 0x02;
 
   static final byte EXPORT_KEY_P2_PRIVATE_AND_PUBLIC = 0x00;
   static final byte EXPORT_KEY_P2_PUBLIC_ONLY = 0x01;
 
-  static final byte TLV_PUB_KEY = (byte) 0x80;
-  static final byte TLV_PRIV_KEY = (byte) 0x81;
-  static final byte TLV_CHAIN_CODE = (byte) 0x82;
   static final byte TLV_APPLICATION_INFO_TEMPLATE = (byte) 0xA4;
 
-  public static final String APPLET_AID = "53746174757357616C6C6574417070";
-  public static final byte[] APPLET_AID_BYTES = Hex.decode(APPLET_AID);
-
   private final CardChannel apduChannel;
   private SecureChannelSession secureChannel;
 
-  public WalletAppletCommandSet(CardChannel apduChannel) {
+  public KeycardCommandSet(CardChannel apduChannel) {
     this.apduChannel = apduChannel;
+    this.secureChannel = new SecureChannelSession();
   }
 
-  public void setSecureChannel(SecureChannelSession secureChannel) {
+  protected void setSecureChannel(SecureChannelSession secureChannel) {
     this.secureChannel = secureChannel;
   }
 
   /**
-   * Selects the applet. The applet is assumed to have been installed with its default AID. The returned data is a
-   * public key which must be used to initialize the secure channel.
-   *
-   * @return the raw card response
-   * @throws IOException communication error
+   * Returns the current pairing data.
    */
+  public Pairing getPairing() {
+    return secureChannel.getPairing();
+  }
+
   /**
-   * Selects the applet. The applet is assumed to have been installed with its default AID. The returned data is a
-   * public key which must be used to initialize the secure channel.
+   * Sets the pairing data.
+   * @param pairing data from an existing pairing
+   */
+  public void setPairing(Pairing pairing) {
+    secureChannel.setPairing(pairing);
+  }
+
+  /**
+   * Selects the default instance of the Keycard applet. The applet is assumed to have been installed with its default
+   * AID. The returned data is a public key which must be used to initialize the secure channel.
    *
    * @return the raw card response
    * @throws IOException communication error
    */
   public APDUResponse select() throws IOException {
-    APDUCommand selectApplet = new APDUCommand(0x00, 0xA4, 4, 0, APPLET_AID_BYTES);
+    return select(Identifiers.KEYCARD_DEFAULT_INSTANCE_IDX);
+  }
+
+  /**
+   * Selects a Keycard instance. The applet is assumed to have been installed with its default AID. The returned data is
+   * a public key which must be used to initialize the secure channel.
+   *
+   * @param instanceIdx the instance index
+   * @return the raw card response
+   * @throws IOException communication error
+   */
+  public APDUResponse select(int instanceIdx) throws IOException {
+    APDUCommand selectApplet = new APDUCommand(0x00, 0xA4, 4, 0, Identifiers.getKeycardInstanceAID(instanceIdx));
     APDUResponse resp =  apduChannel.send(selectApplet);
 
     if (resp.getSw() == 0x9000) {
-      byte[] keyData = extractPublicKeyFromSelect(resp.getData());
-      this.secureChannel = new SecureChannelSession(keyData);
+      this.secureChannel.generateSecret(extractPublicKeyFromSelect(resp.getData()));
+      this.secureChannel.reset();
     }
 
     return resp;
@@ -98,7 +128,6 @@ public class WalletAppletCommandSet {
   /**
    * Opens the secure channel. Calls the corresponding method of the SecureChannel class.
    *
-   * @return the raw card response
    * @throws IOException communication error
    */
   public void autoOpenSecureChannel() throws IOException {
@@ -111,17 +140,28 @@ public class WalletAppletCommandSet {
    * @throws IOException communication error
    */
   public void autoPair(String pairingPassword) throws IOException {
+    byte[] secret = pairingPasswordToSecret(pairingPassword);
+
+    secureChannel.autoPair(apduChannel, secret);
+  }
+
+  /**
+   * Converts a pairing password to a binary pairing secret.
+   *
+   * @param pairingPassword the pairing password
+   * @return the pairing secret
+   */
+  public byte[] pairingPasswordToSecret(String pairingPassword) {
     SecretKey key;
 
     try {
-      SecretKeyFactory skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
-      PBEKeySpec spec = new PBEKeySpec(pairingPassword.toCharArray(), "Status Hardware Wallet Lite".getBytes(), 50000, 32 * 8);
+      SecretKeyFactory skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256", "BC");
+      PBEKeySpec spec = new PBEKeySpec(pairingPassword.toCharArray(), "Keycard Pairing Password Salt".getBytes(), 50000, 32 * 8);
       key = skf.generateSecret(spec);
     } catch (Exception e) {
       throw new RuntimeException("Is Bouncycastle correctly initialized?");
     }
-
-    secureChannel.autoPair(apduChannel, key.getEncoded());
+    return key.getEncoded();
   }
 
   /**
@@ -198,29 +238,15 @@ public class WalletAppletCommandSet {
   }
 
   /**
-   * Sends a GET STATUS APDU to retrieve the APPLICATION STATUS template and reads the byte indicating public key
-   * derivation support.
+   * Sends a SET NDEF APDU.
    *
-   * @return whether public key derivation is supported or not
+   * @param ndef the data field of the APDU
+   * @return the raw card response
    * @throws IOException communication error
    */
-  public boolean getPublicKeyDerivationSupport() throws IOException {
-    APDUResponse resp = getStatus(GET_STATUS_P1_APPLICATION);
-    byte[] data = resp.getData();
-    return data[data.length - 1] != 0x00;
-  }
-
-  /**
-   * Sends a GET STATUS APDU to retrieve the APPLICATION STATUS template and reads the byte indicating key initialization
-   * status
-   *
-   * @return whether public key derivation is supported or not
-   * @throws IOException communication error
-   */
-  public boolean getKeyInitializationStatus() throws IOException {
-    APDUResponse resp = getStatus(GET_STATUS_P1_APPLICATION);
-    byte[] data = resp.getData();
-    return data[data.length - 4] != 0x00;
+  public APDUResponse setNDEF(byte[] ndef) throws IOException {
+    APDUCommand setNDEF = secureChannel.protectedCommand(0x80, INS_SET_NDEF, 0, 0, ndef);
+    return secureChannel.transmit(apduChannel, setNDEF);
   }
 
   /**
@@ -276,31 +302,16 @@ public class WalletAppletCommandSet {
   }
 
   /**
-   * Sends a LOAD KEY APDU. The given private key and chain code are formatted as a raw binary seed and the P1 of
-   * the command is set to LOAD_KEY_P1_SEED (0x03). This works on cards which support public key derivation.
-   * The loaded keyset is extended and support further key derivation.
+   * Sends a LOAD KEY APDU. The given seed is sent as-is and the P1 of the command is set to LOAD_KEY_P1_SEED (0x03).
+   * This works on cards which support public key derivation. The loaded keyset is extended and support further
+   * key derivation.
    *
-   * @param aPrivate a private key
-   * @param chainCode the chain code
+   * @param seed the binary seed
    * @return the raw card response
    * @throws IOException communication error
    */
-  public APDUResponse loadKey(PrivateKey aPrivate, byte[] chainCode) throws IOException {
-    byte[] privateKey = ((ECPrivateKey) aPrivate).getD().toByteArray();
-
-    int privLen = privateKey.length;
-    int privOff = 0;
-
-    if(privateKey[0] == 0x00) {
-      privOff++;
-      privLen--;
-    }
-
-    byte[] data = new byte[chainCode.length + privLen];
-    System.arraycopy(privateKey, privOff, data, 0, privLen);
-    System.arraycopy(chainCode, 0, data, privLen, chainCode.length);
-
-    return loadKey(data, LOAD_KEY_P1_SEED);
+  public APDUResponse loadKey(byte[] seed) throws IOException {
+    return loadKey(seed, LOAD_KEY_P1_SEED);
   }
 
   /**
@@ -327,10 +338,10 @@ public class WalletAppletCommandSet {
    * @throws IOException communication error
    */
   public APDUResponse loadKey(KeyPair keyPair, boolean omitPublicKey, byte[] chainCode) throws IOException {
-    byte[] publicKey = omitPublicKey ? null : ((ECPublicKey) keyPair.getPublic()).getQ().getEncoded(false);
+    byte[] publicKey = ((ECPublicKey) keyPair.getPublic()).getQ().getEncoded(false);
     byte[] privateKey = ((ECPrivateKey) keyPair.getPrivate()).getD().toByteArray();
 
-    return loadKey(publicKey, privateKey, chainCode);
+    return loadKey(new BIP32KeyPair(privateKey, chainCode, publicKey), omitPublicKey);
   }
 
   /**
@@ -345,59 +356,23 @@ public class WalletAppletCommandSet {
    * @throws IOException communication error
    */
   public APDUResponse loadKey(byte[] publicKey, byte[] privateKey, byte[] chainCode) throws IOException {
-    int privLen = privateKey.length;
-    int privOff = 0;
+    return loadKey(new BIP32KeyPair(privateKey, chainCode, publicKey), publicKey == null);
+  }
 
-    if(privateKey[0] == 0x00) {
-      privOff++;
-      privLen--;
-    }
-
-    int off = 0;
-    int totalLength = publicKey == null ? 0 : (publicKey.length + 2);
-    totalLength += (privLen + 2);
-    totalLength += chainCode == null ? 0 : (chainCode.length + 2);
-
-    if (totalLength > 127) {
-      totalLength += 3;
-    } else {
-      totalLength += 2;
-    }
-
-    byte[] data = new byte[totalLength];
-    data[off++] = (byte) 0xA1;
-
-    if (totalLength > 127) {
-      data[off++] = (byte) 0x81;
-      data[off++] = (byte) (totalLength - 3);
-    } else {
-      data[off++] = (byte) (totalLength - 2);
-    }
-
-    if (publicKey != null) {
-      data[off++] = TLV_PUB_KEY;
-      data[off++] = (byte) publicKey.length;
-      System.arraycopy(publicKey, 0, data, off, publicKey.length);
-      off += publicKey.length;
-    }
-
-    data[off++] = TLV_PRIV_KEY;
-    data[off++] = (byte) privLen;
-    System.arraycopy(privateKey, privOff, data, off, privLen);
-    off += privLen;
+  public APDUResponse loadKey(BIP32KeyPair keyPair) throws IOException {
+    return loadKey(keyPair, false);
+  }
 
+  public APDUResponse loadKey(BIP32KeyPair keyPair, boolean omitPublic)  throws IOException {
     byte p1;
 
-    if (chainCode != null) {
+    if (keyPair.isExtended()) {
       p1 = LOAD_KEY_P1_EXT_EC;
-      data[off++] = (byte) TLV_CHAIN_CODE;
-      data[off++] = (byte) chainCode.length;
-      System.arraycopy(chainCode, 0, data, off, chainCode.length);
     } else {
       p1 = LOAD_KEY_P1_EC;
     }
 
-    return loadKey(data, p1);
+    return loadKey(keyPair.toTLV(!omitPublic), p1);
   }
 
   /**
@@ -437,53 +412,113 @@ public class WalletAppletCommandSet {
   }
 
   /**
-   * Sends a SIGN APDU. The dataType is P1 as defined in the applet. The isFirst and isLast arguments are used to form
-   * the P2 parameter. The data is the data to sign, or part of it. Only when sending the last block a signature is
-   * generated and thus returned. When signing a precomputed hash it must be done in a single block, so isFirst and
-   * isLast will always be true at the same time.
+   * Sends a GENERATE KEY APDU.
    *
-   * @param data the data to sign
-   * @param dataType the P1 parameter
-   * @param isFirst whether this is the first block of the command or not
-   * @param isLast whether this is the last block of the command or not
    * @return the raw card response
    * @throws IOException communication error
    */
-  public APDUResponse sign(byte[] data, byte dataType, boolean isFirst, boolean isLast) throws IOException {
-    byte p2 = (byte) ((isFirst ? 0x01 : 0x00) | (isLast ? 0x80 : 0x00));
-    APDUCommand sign = secureChannel.protectedCommand(0x80, INS_SIGN, dataType, p2, data);
+  public APDUResponse generateKey() throws IOException {
+    APDUCommand generateKey = secureChannel.protectedCommand(0x80, INS_GENERATE_KEY, 0, 0, new byte[0]);
+    return secureChannel.transmit(apduChannel, generateKey);
+  }
+
+  /**
+   * Sends a DUPLICATE KEY APDU. The P1 is set to 00, P2 to the entropy count and the data is the first entropy piece.
+   * This starts a duplication session. Requires an open Secure Channel and authenticated PIN.
+   *
+   * @param entropyCount the number of entropy pieces to expect, including the one in this APDU
+   * @param firstEntropy a random 32-byte number
+   * @return the raw card response
+   * @throws IOException communication error
+   */
+  public APDUResponse duplicateKeyStart(int entropyCount, byte[] firstEntropy) throws IOException {
+    APDUCommand duplicateKeyStart = secureChannel.protectedCommand(0x80, INS_DUPLICATE_KEY, DUPLICATE_KEY_P1_START, entropyCount, firstEntropy);
+    return secureChannel.transmit(apduChannel, duplicateKeyStart);
+  }
+
+  /**
+   * Sends a DUPLICATE KEY APDU. The P1 is set to 01 and the data is the entropy. This adds entropy and does not require
+   * a Secure Channel or authenticated PIN.
+   *
+   * @param entropy a random 32-byte number
+   * @return the raw card response
+   * @throws IOException communication error
+   */
+  public APDUResponse duplicateKeyAddEntropy(byte[] entropy) throws IOException {
+    APDUCommand duplicateKeyAddEntropy = new APDUCommand(0x80, INS_DUPLICATE_KEY, DUPLICATE_KEY_P1_ADD_ENTROPY, 0, secureChannel.oneShotEncrypt(entropy));
+    return apduChannel.send(duplicateKeyAddEntropy);
+  }
+
+  /**
+   * Sends a DUPLICATE KEY APDU. The P1 is set to 02. This exports the encrypted master key including chaining code.
+   *
+   * @return the raw card response
+   * @throws IOException communication error
+   */
+  public APDUResponse duplicateKeyExport() throws IOException {
+    APDUCommand duplicateKeyExport = secureChannel.protectedCommand(0x80, INS_DUPLICATE_KEY, DUPLICATE_KEY_P1_EXPORT, 0, new byte[0]);
+    return secureChannel.transmit(apduChannel, duplicateKeyExport);
+  }
+
+  /**
+   * Sends a DUPLICATE KEY APDU. The P1 is set to 03. This imports an encrypted master key including chaining code. The
+   * response data contains the key UID of the imported key.
+   *
+   * @param key the key, exported from another card in the same duplication session.
+   * @return the raw card response
+   * @throws IOException communication error
+   */
+  public APDUResponse duplicateKeyImport(byte[] key) throws IOException {
+    APDUCommand duplicateKeyImport = secureChannel.protectedCommand(0x80, INS_DUPLICATE_KEY, DUPLICATE_KEY_P1_IMPORT, 0, key);
+    return secureChannel.transmit(apduChannel, duplicateKeyImport);
+  }
+
+  /**
+   * Sends a SIGN APDU. This signs a precomputed hash so the input must be exactly 32-bytes long.
+   *
+   * @param data the data to sign
+   * @return the raw card response
+   * @throws IOException communication error
+   */
+  public APDUResponse sign(byte[] data) throws IOException {
+    APDUCommand sign = secureChannel.protectedCommand(0x80, INS_SIGN, 0x00, 0x00, data);
     return secureChannel.transmit(apduChannel, sign);
   }
 
   /**
-   * Sends a DERIVE KEY APDU. The data is encrypted and sent as-is. The P1 and P2 parameters are forced to 0, meaning
-   * that the derivation starts from the master key and is non-assisted.
+   * Sends a DERIVE KEY APDU with the given key path.
+   *
+   * @param keypath the string key path
+   * @return the raw card response
+   * @throws IOException communication error
+   */
+  public APDUResponse deriveKey(String keypath) throws IOException {
+    KeyPath path = new KeyPath(keypath);
+    return deriveKey(path.getData(), path.getSource());
+  }
+
+  /**
+   * Sends a DERIVE KEY APDU. The data is encrypted and sent as-is. The P1 is forced to 0, meaning that the derivation
+   * starts from the master key.
    *
    * @param data the raw key path
    * @return the raw card response
    * @throws IOException communication error
    */
   public APDUResponse deriveKey(byte[] data) throws IOException {
-    return deriveKey(data, DERIVE_P1_SOURCE_MASTER, false, false);
+    return deriveKey(data, DERIVE_P1_SOURCE_MASTER);
   }
 
   /**
-   * Sends a DERIVE KEY APDU. The data is encrypted and sent as-is. The reset and assisted parameters are combined to
-   * form P1. The isPublicKey parameter is used for P2.
+   * Sends a DERIVE KEY APDU. The data is encrypted and sent as-is. The source parameter is used as P1.
    *
    * @param data the raw key path or a public key
    * @param source the source to start derivation
-   * @param assisted whether we are doing assisted derivation or not
-   * @param isPublicKey whether we are sending a public key or a key path (only make sense during assisted derivation)
    * @return the raw card response
    * @throws IOException communication error
    */
-  public APDUResponse deriveKey(byte[] data, int source, boolean assisted, boolean isPublicKey) throws IOException {
-    byte p1 = assisted ? DERIVE_P1_ASSISTED_MASK : 0;
-    p1 |= source;
-    byte p2 = isPublicKey ? DERIVE_P2_PUBLIC_KEY : DERIVE_P2_KEY_PATH;
-
-    APDUCommand deriveKey = secureChannel.protectedCommand(0x80, INS_DERIVE_KEY, p1, p2, data);
+  public APDUResponse deriveKey(byte[] data, int source) throws IOException {
+    APDUCommand deriveKey = secureChannel.protectedCommand(0x80, INS_DERIVE_KEY, source, 0x00, data);
     return secureChannel.transmit(apduChannel, deriveKey);
   }
 
@@ -500,19 +535,72 @@ public class WalletAppletCommandSet {
   }
 
   /**
-   * Sends an EXPORT KEY APDU. The keyPathIndex is used as P1. Valid values are defined in the applet itself
+   * Sends an EXPORT KEY APDU to export the current key.
    *
-   * @param keyPathIndex the P1 parameter
+   * @param publicOnly exports only the public key
+   * @return the raw card reponse
+   * @throws IOException communication error
+   */
+  public APDUResponse exportCurrentKey(boolean publicOnly) throws IOException {
+    return exportKey(EXPORT_KEY_P1_CURRENT, publicOnly, new byte[0]);
+  }
+
+  /**
+   * Sends an EXPORT KEY APDU. Performs derivation of the given keypath and optionally makes it the current key.
+   *
+   * @param keyPath the keypath to export
+   * @param makeCurrent if the key should be made current or not
    * @param publicOnly the P2 parameter
    * @return the raw card response
    * @throws IOException communication error
    */
-  public APDUResponse exportKey(byte keyPathIndex, boolean publicOnly) throws IOException {
+  public APDUResponse exportKey(String keyPath, boolean makeCurrent, boolean publicOnly) throws IOException {
+    KeyPath path = new KeyPath(keyPath);
+    return exportKey(path.getData(), path.getSource(), makeCurrent, publicOnly);
+  }
+
+  /**
+   * Sends an EXPORT KEY APDU. Performs derivation of the given keypath and optionally makes it the current key.
+   *
+   * @param keyPath the keypath to export
+   * @param makeCurrent if the key should be made current or not
+   * @param publicOnly the P2 parameter
+   * @return the raw card response
+   * @throws IOException communication error
+   */
+  public APDUResponse exportKey(byte[] keyPath, int source, boolean makeCurrent, boolean publicOnly) throws IOException {
+    int p1 = source | (makeCurrent ? EXPORT_KEY_P1_DERIVE_AND_MAKE_CURRENT : EXPORT_KEY_P1_DERIVE);
+    return exportKey(p1, publicOnly, keyPath);
+  }
+
+  /**
+   * Sends an EXPORT KEY APDU. The parameters are sent as-is.
+   *
+   * @param derivationOptions the P1 parameter
+   * @param publicOnly the P2 parameter
+   * @param keypath the data parameter
+   * @return the raw card response
+   * @throws IOException communication error
+   */
+  public APDUResponse exportKey(int derivationOptions, boolean publicOnly, byte[] keypath) throws IOException {
     byte p2 = publicOnly ? EXPORT_KEY_P2_PUBLIC_ONLY : EXPORT_KEY_P2_PRIVATE_AND_PUBLIC;
-    APDUCommand exportKey = secureChannel.protectedCommand(0x80, INS_EXPORT_KEY, keyPathIndex, p2, new byte[0]);
+    APDUCommand exportKey = secureChannel.protectedCommand(0x80, INS_EXPORT_KEY, derivationOptions, p2, keypath);
     return secureChannel.transmit(apduChannel, exportKey);
   }
 
+  /**
+   * Sends the INIT command to the card.
+   *
+   * @param pin the PIN
+   * @param puk the PUK
+   * @param pairingPassword pairing password
+   * @return the raw card response
+   * @throws IOException communication error
+   */
+  public APDUResponse init(String pin, String puk, String pairingPassword) throws IOException {
+    return this.init(pin, puk, pairingPasswordToSecret(pairingPassword));
+  }
+
   /**
    * Sends the INIT command to the card.
    *
@@ -531,12 +619,6 @@ public class WalletAppletCommandSet {
   }
 
   private byte[] extractPublicKeyFromSelect(byte[] select) {
-    if (select[0] == TLV_APPLICATION_INFO_TEMPLATE) {
-      return Arrays.copyOfRange(select, 22, 22 + select[21]);
-    } else if (select[0] == TLV_PUB_KEY) {
-      return Arrays.copyOfRange(select, 2, select.length);
-    } else {
-      throw new RuntimeException("Unexpected card response");
-    }
+    return new ApplicationInfo(select).getSecureChannelPubKey();
   }
 }

lib/src/main/java/im/status/keycard/applet/Mnemonic.java

@@ -0,0 +1,177 @@
+package im.status.keycard.applet;
+
+import javax.crypto.SecretKey;
+import javax.crypto.SecretKeyFactory;
+import javax.crypto.spec.PBEKeySpec;
+import java.io.IOException;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Scanner;
+
+public class Mnemonic {
+  private final static int WORDLIST_SIZE = 2048;
+
+  private short[] indexes;
+  private String[] wordlist;
+
+  /**
+   * Constructs a Mnemonic object from the response of the GENERATE MNEMONIC APDU
+   *
+   * @param data the card response
+   */
+  public Mnemonic(byte[] data) {
+    this.indexes = new short[data.length/2];
+
+    for (int i = 0; i < this.indexes.length; i++) {
+      this.indexes[i] = (short) (((data[i * 2] & 0xff) << 8) | (data[(i * 2) + 1] & 0xff));
+    }
+  }
+
+  /**
+   * Sets the wordlist, which must be a list of 2048 words.
+   *
+   * @param wordlist
+   */
+  public void setWordlist(String[] wordlist) {
+    if (wordlist.length != WORDLIST_SIZE) {
+      throw new IllegalArgumentException("The list must contain exactly 2048 entries");
+    }
+
+    this.wordlist = wordlist;
+  }
+
+  /**
+   * Retrieves the official BIP39 english wordlist from GitHub.
+   *
+   * @throws IOException network error
+   */
+  public void fetchBIP39EnglishWordlist() throws IOException {
+    URL remoteList = new URL("https://raw.githubusercontent.com/bitcoin/bips/master/bip-0039/english.txt");
+    Scanner scanner = new Scanner(remoteList.openStream());
+
+    ArrayList<String> list = new ArrayList<>();
+
+    while(scanner.hasNextLine()) {
+      list.add(scanner.nextLine());
+    }
+
+    scanner.close();
+
+    if (list.size() != WORDLIST_SIZE) {
+      throw new IllegalArgumentException("The list must contain exactly 2048 entries");
+    }
+
+    this.wordlist = new String[WORDLIST_SIZE];
+    list.toArray(this.wordlist);
+  }
+
+  /**
+   * Gets the indexes of all words of the mnemonic.
+   * @return indexes
+   */
+  public short[] getIndexes() {
+    return indexes;
+  }
+
+  /**
+   * The words of the mnemonic phrase. Requires the wordlist to be non-null.
+   *
+   * @return the array of words
+   */
+  public String[] getWords() {
+    if (this.wordlist == null) {
+      throw new IllegalStateException("The wordlist must be set first");
+    }
+
+    String[] words = new String[this.indexes.length];
+
+    for (int i = 0; i < this.indexes.length; i++) {
+      words[i] = this.wordlist[this.indexes[i]];
+    }
+
+    return words;
+  }
+
+  /**
+   * The representation of this object as a mnemonic phrase. Requires the wordlist to be non-null.
+   * @return the mnemonic phrase
+   */
+  public String toMnemonicPhrase() {
+    return join(" ", getWords());
+  }
+
+  /**
+   * The binary seed representation of this object, with no password.
+   *
+   * @return the binary seed
+   */
+  public byte[] toBinarySeed() {
+    return toBinarySeed("");
+  }
+
+  /**
+   * The binary seed representation of this object, with a password.
+   *
+   * @param password can be an empty string but not null
+   * @return the binary seed
+   */
+  public byte[] toBinarySeed(String password) {
+    return toBinarySeed(toMnemonicPhrase(), password);
+  }
+
+  /**
+   * The full master key, generated from this mnemonic.
+   *
+   */
+  public BIP32KeyPair toBIP32KeyPair() {
+    return toBIP32KeyPair("");
+  }
+
+  /**
+   * The full master key, generated from this mnemonic with a password.
+   *
+   * @param password can be an empty string but not null
+   * @return the binary seed
+   */
+  public BIP32KeyPair toBIP32KeyPair(String password) {
+    return BIP32KeyPair.fromBinarySeed(toBinarySeed(password));
+  }
+
+  public static byte[] toBinarySeed(String mnemonicPhrase, String password) {
+    SecretKey key;
+
+    try {
+      SecretKeyFactory skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA512", "BC");
+      PBEKeySpec spec = new PBEKeySpec(mnemonicPhrase.toCharArray(), ("mnemonic" + password).getBytes(), 2048, 512);
+      key = skf.generateSecret(spec);
+    } catch (Exception e) {
+      throw new RuntimeException("Is Bouncycastle correctly initialized?");
+    }
+
+    return key.getEncoded();
+  }
+
+  /**
+   * String join. Used instead of Android TextUtils.join or Java 8 String.join method for compatibility reasons.
+   *
+   * @param list the list of words
+   * @param conjunction the conjunction
+   *
+   * @return the joined string
+   */
+  private String join(String conjunction, String[] list) {
+    StringBuilder sb = new StringBuilder();
+    boolean first = true;
+    for (String item : list) {
+      if (first) {
+        first = false;
+      } else {
+        sb.append(conjunction);
+      }
+
+      sb.append(item);
+    }
+
+    return sb.toString();
+  }
+}

lib/src/main/java/im/status/keycard/applet/Pairing.java

@@ -0,0 +1,60 @@
+package im.status.keycard.applet;
+
+import org.bouncycastle.util.encoders.Base64;
+
+import java.util.Arrays;
+
+/**
+ * Stores pairing information.
+ */
+public class Pairing {
+  private byte[] pairingKey;
+  private byte pairingIndex;
+
+  /**
+   * Constructor. The pairingKey and pairingIndex are those generated at the end of a successful pairing.
+   * @param pairingKey the pairing key
+   * @param pairingIndex the pairing index
+   */
+  public Pairing(byte[] pairingKey, byte pairingIndex) {
+    this.pairingKey = pairingKey;
+    this.pairingIndex = pairingIndex;
+  }
+
+  /**
+   * Constructor. Initializes from a byte array previously generated from the toByteArray method
+   * @param fromByteArray the result of a previous toByteArray invocation
+   */
+  public Pairing(byte[] fromByteArray) {
+    pairingIndex = fromByteArray[0];
+    pairingKey = Arrays.copyOfRange(fromByteArray, 1, fromByteArray.length);
+  }
+
+  /**
+   * Constructor. Initializes from a String previously generated from the toBase64 method
+   * @param base64 the result of a previous toBase64 invocation
+   */
+  public Pairing(String base64) {
+    this(Base64.decode(base64));
+  }
+
+  public byte[] getPairingKey() {
+    return pairingKey;
+  }
+
+  public byte getPairingIndex() {
+    return pairingIndex;
+  }
+
+  public byte[] toByteArray() {
+    byte[] res = new byte[pairingKey.length + 1];
+    res[0] = pairingIndex;
+    System.arraycopy(pairingKey, 0, res, 1, pairingKey.length);
+
+    return res;
+  }
+
+  public String toBase64() {
+    return Base64.toBase64String(toByteArray());
+  }
+}

lib/src/main/java/im/status/keycard/applet/RecoverableSignature.java

@@ -0,0 +1,130 @@
+package im.status.keycard.applet;
+
+import org.bouncycastle.asn1.x9.X9ECParameters;
+import org.bouncycastle.asn1.x9.X9IntegerConverter;
+import org.bouncycastle.crypto.ec.CustomNamedCurves;
+import org.bouncycastle.crypto.params.ECDomainParameters;
+import org.bouncycastle.math.ec.ECAlgorithms;
+import org.bouncycastle.math.ec.ECPoint;
+import org.bouncycastle.math.ec.FixedPointUtil;
+import org.bouncycastle.math.ec.custom.sec.SecP256K1Curve;
+
+import java.math.BigInteger;
+import java.util.Arrays;
+
+/**
+ * Signature with recoverable public key.
+ */
+public class RecoverableSignature {
+  private byte[] publicKey;
+  private int recId;
+  private byte[] r;
+  private byte[] s;
+
+  public static final byte TLV_SIGNATURE_TEMPLATE = (byte) 0xA0;
+  public static final byte TLV_ECDSA_TEMPLATE = (byte) 0x30;
+
+  private static final X9ECParameters CURVE_PARAMS = CustomNamedCurves.getByName("secp256k1");
+  static final ECDomainParameters CURVE;
+
+  static {
+    FixedPointUtil.precompute(CURVE_PARAMS.getG());
+    CURVE = new ECDomainParameters(CURVE_PARAMS.getCurve(), CURVE_PARAMS.getG(), CURVE_PARAMS.getN(), CURVE_PARAMS.getH());
+  }
+
+  /**
+   * Parses a signature from the card and calculates the recovery ID.
+   *
+   * @param hash the message being signed
+   * @param tlvData the signature as returned from the card
+   */
+  public RecoverableSignature(byte[] hash, byte[] tlvData) {
+    TinyBERTLV tlv = new TinyBERTLV(tlvData);
+    tlv.enterConstructed(TLV_SIGNATURE_TEMPLATE);
+    publicKey = tlv.readPrimitive(ApplicationInfo.TLV_PUB_KEY);
+    tlv.enterConstructed(TLV_ECDSA_TEMPLATE);
+    r = tlv.readPrimitive(TinyBERTLV.TLV_INT);
+    s = tlv.readPrimitive(TinyBERTLV.TLV_INT);
+
+    recId = -1;
+
+    for (int i = 0; i < 4; i++) {
+      byte[] candidate = recoverFromSignature(i, new BigInteger(1, hash), new BigInteger(1, r), new BigInteger(1, s));
+
+      if (Arrays.equals(candidate, publicKey)) {
+        recId = i;
+        break;
+      }
+    }
+
+    if (recId == -1) {
+      throw new IllegalArgumentException("Unrecoverable signature, cannot find recId");
+    }
+  }
+
+  /**
+   * The public key associated to this signature.
+   *
+   * @return the public key associated to this signature
+   */
+  public byte[] getPublicKey() {
+    return publicKey;
+  }
+
+  /**
+   * The recovery ID
+   *
+   * @return recovery ID
+   */
+  public int getRecId() {
+    return recId;
+  }
+
+  /**
+   * The R value.
+   *
+   * @return r
+   */
+  public byte[] getR() {
+    return r;
+  }
+
+  /**
+   * The S value
+   * @return s
+   */
+  public byte[] getS() {
+    return s;
+  }
+
+  private static byte[] recoverFromSignature(int recId, BigInteger e, BigInteger r, BigInteger s) {
+    BigInteger n = CURVE.getN();
+    BigInteger i = BigInteger.valueOf((long) recId / 2);
+    BigInteger x = r.add(i.multiply(n));
+    BigInteger prime = SecP256K1Curve.q;
+
+    if (x.compareTo(prime) >= 0) {
+      return null;
+    }
+
+    ECPoint R = decompressKey(x, (recId & 1) == 1);
+
+    if (!R.multiply(n).isInfinity()) {
+      return null;
+    }
+
+    BigInteger eInv = BigInteger.ZERO.subtract(e).mod(n);
+    BigInteger rInv = r.modInverse(n);
+    BigInteger srInv = rInv.multiply(s).mod(n);
+    BigInteger eInvrInv = rInv.multiply(eInv).mod(n);
+    ECPoint q = ECAlgorithms.sumOfTwoMultiplies(CURVE.getG(), eInvrInv, R, srInv);
+    return q.getEncoded(false);
+  }
+
+  private static ECPoint decompressKey(BigInteger xBN, boolean yBit) {
+    X9IntegerConverter x9 = new X9IntegerConverter();
+    byte[] compEnc = x9.integerToBytes(xBN, 1 + x9.getByteLength(CURVE.getCurve()));
+    compEnc[0] = (byte)(yBit ? 0x03 : 0x02);
+    return CURVE.getCurve().decodePoint(compEnc);
+  }
+}

lib/src/main/java/im/status/keycard/applet/SecureChannelSession.java

@@ -1,16 +1,16 @@
-package im.status.hardwallet_lite_android.wallet;
+package im.status.keycard.applet;
 
-import im.status.hardwallet_lite_android.io.APDUCommand;
-import im.status.hardwallet_lite_android.io.APDUException;
-import im.status.hardwallet_lite_android.io.APDUResponse;
-import im.status.hardwallet_lite_android.io.CardChannel;
-import org.spongycastle.crypto.engines.AESEngine;
-import org.spongycastle.crypto.macs.CBCBlockCipherMac;
-import org.spongycastle.crypto.params.KeyParameter;
-import org.spongycastle.jce.ECNamedCurveTable;
-import org.spongycastle.jce.interfaces.ECPublicKey;
-import org.spongycastle.jce.spec.ECParameterSpec;
-import org.spongycastle.jce.spec.ECPublicKeySpec;
+import im.status.keycard.io.APDUCommand;
+import im.status.keycard.io.APDUException;
+import im.status.keycard.io.APDUResponse;
+import im.status.keycard.io.CardChannel;
+import org.bouncycastle.crypto.engines.AESEngine;
+import org.bouncycastle.crypto.macs.CBCBlockCipherMac;
+import org.bouncycastle.crypto.params.KeyParameter;
+import org.bouncycastle.jce.ECNamedCurveTable;
+import org.bouncycastle.jce.interfaces.ECPublicKey;
+import org.bouncycastle.jce.spec.ECParameterSpec;
+import org.bouncycastle.jce.spec.ECPublicKeySpec;
 
 import javax.crypto.Cipher;
 import javax.crypto.KeyAgreement;
@@ -42,9 +42,8 @@ public class SecureChannelSession {
 
   private byte[] secret;
   private byte[] publicKey;
-  private byte[] pairingKey;
   private byte[] iv;
-  private byte pairingIndex;
+  private Pairing pairing;
   private Cipher sessionCipher;
   private CBCBlockCipherMac sessionMac;
   private SecretKeySpec sessionEncKey;
@@ -53,32 +52,33 @@ public class SecureChannelSession {
   private boolean open;
 
   /**
-   * Constructs a SecureChannel session on the client. The client should generate a fresh key pair for each session.
-   * The public key of the card is used as input for the EC-DH algorithm. The output is stored as the secret.
-   *
-   * @param keyData the public key returned by the applet as response to the SELECT command
+   * Constructs a SecureChannel session on the client.
    */
-  public SecureChannelSession(byte[] keyData) {
+  public SecureChannelSession() {
       random = new SecureRandom();
-      generateSecret(keyData);
       open = false;
   }
 
+  /**
+   * Generates a pairing secret. This should be called before each session. The public key of the card is used as input
+   * for the EC-DH algorithm. The output is stored as the secret.
+   *
+   * @param keyData the public key returned by the applet as response to the SELECT command
+   */
   public void generateSecret(byte[] keyData) {
     try {
-      random = new SecureRandom();
       ECParameterSpec ecSpec = ECNamedCurveTable.getParameterSpec("secp256k1");
-      KeyPairGenerator g = KeyPairGenerator.getInstance("ECDH");
+      KeyPairGenerator g = KeyPairGenerator.getInstance("ECDH", "BC");
       g.initialize(ecSpec, random);
 
       KeyPair keyPair = g.generateKeyPair();
 
       publicKey = ((ECPublicKey) keyPair.getPublic()).getQ().getEncoded(false);
-      KeyAgreement keyAgreement = KeyAgreement.getInstance("ECDH");
+      KeyAgreement keyAgreement = KeyAgreement.getInstance("ECDH", "BC");
       keyAgreement.init(keyPair.getPrivate());
 
       ECPublicKeySpec cardKeySpec = new ECPublicKeySpec(ecSpec.getCurve().decodePoint(keyData), ecSpec);
-      ECPublicKey cardKey = (ECPublicKey) KeyFactory.getInstance("ECDSA").generatePublic(cardKeySpec);
+      ECPublicKey cardKey = (ECPublicKey) KeyFactory.getInstance("ECDSA", "BC").generatePublic(cardKeySpec);
 
       keyAgreement.doPhase(cardKey, true);
       secret = keyAgreement.generateSecret();
@@ -96,11 +96,19 @@ public class SecureChannelSession {
   }
 
   /**
-   * Returns the pairing index
-   * @return the pairing index
+   * Returns the pairing information
+   * @return the pairing information
    */
-  public byte getPairingIndex() {
-    return pairingIndex;
+  public Pairing getPairing() {
+    return pairing;
+  }
+
+  /**
+   * Sets pairing information needed to open a secure channel.
+   * @param pairing the pairing information
+   */
+  public void setPairing(Pairing pairing) {
+    this.pairing = pairing;
   }
 
   /**
@@ -108,11 +116,10 @@ public class SecureChannelSession {
    * Follows the specifications from the SECURE_CHANNEL.md document.
    *
    * @param apduChannel the apdu channel
-   * @return the card response
    * @throws IOException communication error
    */
   public void autoOpenSecureChannel(CardChannel apduChannel) throws IOException {
-    APDUResponse response = openSecureChannel(apduChannel, pairingIndex, publicKey);
+    APDUResponse response = openSecureChannel(apduChannel, pairing.getPairingIndex(), publicKey);
 
     if (response.getSw() != 0x9000) {
       throw new IOException("OPEN SECURE CHANNEL failed");
@@ -140,14 +147,14 @@ public class SecureChannelSession {
     try {
       MessageDigest md = MessageDigest.getInstance("SHA512");
       md.update(secret);
-      md.update(pairingKey);
+      md.update(pairing.getPairingKey());
       byte[] data = response.getData();
       byte[] keyData = md.digest(Arrays.copyOf(data, SC_SECRET_LENGTH));
       iv = Arrays.copyOfRange(data, SC_SECRET_LENGTH, data.length);
 
       sessionEncKey = new SecretKeySpec(Arrays.copyOf(keyData, SC_SECRET_LENGTH), "AES");
       sessionMacKey = new KeyParameter(keyData, SC_SECRET_LENGTH, SC_SECRET_LENGTH);
-      sessionCipher = Cipher.getInstance("AES/CBC/ISO7816-4Padding");
+      sessionCipher = Cipher.getInstance("AES/CBC/ISO7816-4Padding", "BC");
       sessionMac = new CBCBlockCipherMac(new AESEngine(), 128, null);
       open = true;
     } catch(Exception e) {
@@ -188,7 +195,7 @@ public class SecureChannelSession {
     MessageDigest md;
 
     try {
-      md = MessageDigest.getInstance("SHA256");
+      md = MessageDigest.getInstance("SHA256", "BC");
     } catch(Exception e) {
       throw new RuntimeException("Is BouncyCastle in the classpath?", e);
     }
@@ -211,8 +218,7 @@ public class SecureChannelSession {
 
     respData = resp.getData();
     md.update(sharedSecret);
-    pairingKey = md.digest(Arrays.copyOfRange(respData, 1, respData.length));
-    pairingIndex = respData[0];
+    pairing = new Pairing(md.digest(Arrays.copyOfRange(respData, 1, respData.length)), respData[0]);
   }
 
   /**
@@ -222,7 +228,7 @@ public class SecureChannelSession {
    * @throws IOException communication error
    */
   public void autoUnpair(CardChannel apduChannel) throws IOException {
-    APDUResponse resp = unpair(apduChannel, pairingIndex);
+    APDUResponse resp = unpair(apduChannel, pairing.getPairingIndex());
 
     if (resp.getSw() != 0x9000) {
       throw new IOException("Unpairing failed");
@@ -281,8 +287,8 @@ public class SecureChannelSession {
    * @throws IOException communication error
    */
   public APDUResponse pair(CardChannel apduChannel, byte p1, byte[] data) throws IOException {
-    APDUCommand openSecureChannel = new APDUCommand(0x80, INS_PAIR, p1, 0, data);
-    return transmit(apduChannel, openSecureChannel);
+    APDUCommand pair = new APDUCommand(0x80, INS_PAIR, p1, 0, data);
+    return transmit(apduChannel, pair);
   }
 
   /**
@@ -294,22 +300,21 @@ public class SecureChannelSession {
    * @throws IOException communication error
    */
   public APDUResponse unpair(CardChannel apduChannel, byte p1) throws IOException {
-    APDUCommand openSecureChannel = protectedCommand(0x80, INS_UNPAIR, p1, 0, new byte[0]);
-    return transmit(apduChannel, openSecureChannel);
+    APDUCommand unpair = protectedCommand(0x80, INS_UNPAIR, p1, 0, new byte[0]);
+    return transmit(apduChannel, unpair);
   }
 
   /**
    * Unpair all other clients
    *
    * @param apduChannel the apdu channel
-   * @return the raw card response
    * @throws IOException communication error
    */
   public void unpairOthers(CardChannel apduChannel) throws IOException, APDUException {
     for (int i = 0; i < PAIRING_MAX_CLIENT_COUNT; i++) {
-      if (i != pairingIndex) {
-        APDUCommand openSecureChannel = protectedCommand(0x80, INS_UNPAIR, i, 0, new byte[0]);
-        transmit(apduChannel, openSecureChannel).checkOK();
+      if (i != pairing.getPairingIndex()) {
+        APDUCommand unpair = protectedCommand(0x80, INS_UNPAIR, i, 0, new byte[0]);
+        transmit(apduChannel, unpair).checkOK();
       }
     }
   }
@@ -434,7 +439,7 @@ public class SecureChannelSession {
       random.nextBytes(iv);
       IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);
       sessionEncKey = new SecretKeySpec(secret, "AES");
-      sessionCipher = Cipher.getInstance("AES/CBC/ISO7816-4Padding");
+      sessionCipher = Cipher.getInstance("AES/CBC/ISO7816-4Padding", "BC");
       sessionCipher.init(Cipher.ENCRYPT_MODE, sessionEncKey, ivParameterSpec);
       initData = sessionCipher.doFinal(initData);
       byte[] encrypted = new byte[1 + publicKey.length + iv.length + initData.length];
@@ -453,7 +458,7 @@ public class SecureChannelSession {
    * would only make things wrong.
    *
    */
-  void setOpen() {
+  protected void setOpen() {
     open = true;
   }
 

lib/src/main/java/im/status/keycard/applet/TinyBERTLV.java

@@ -0,0 +1,122 @@
+package im.status.keycard.applet;
+
+import java.util.Arrays;
+
+/**
+ * Tiny BER-TLV implementation. Not for general usage, but fast and easy to use for this project.
+ */
+public class TinyBERTLV {
+  public static final byte TLV_BOOL = (byte) 0x01;
+  public static final byte TLV_INT = (byte) 0x02;
+
+  public static final int END_OF_TLV = (int) 0xffffffff;
+
+  private byte[] buffer;
+  private int pos;
+
+  public TinyBERTLV(byte[] buffer) {
+    this.buffer = buffer;
+    this.pos = 0;
+  }
+
+  /**
+   * Enters a constructed TLV with the given tag
+   *
+   * @param tag the tag to enter
+   * @return the length of the TLV
+   * @throws IllegalArgumentException if the next tag does not match the given one
+   */
+  public int enterConstructed(int tag) throws IllegalArgumentException {
+    checkTag(tag, readTag());
+    return readLength();
+  }
+
+  /**
+   * Reads a primitive TLV with the given tag
+   *
+   * @param tag the tag to read
+   * @return the body of the TLV
+   * @throws IllegalArgumentException if the next tag does not match the given one
+   */
+  public byte[] readPrimitive(int tag) throws IllegalArgumentException {
+    checkTag(tag, readTag());
+    int len = readLength();
+    pos += len;
+    return Arrays.copyOfRange(buffer, (pos - len), pos);
+  }
+
+  /**
+   * Reads a boolean TLV.
+   *
+   * @return the boolean value of the TLV
+   * @throws IllegalArgumentException if the next tag is not a boolean
+   */
+  public boolean readBoolean() throws IllegalArgumentException {
+    byte[] val = readPrimitive(TLV_BOOL);
+    return ((val[0] & 0xff) == 0xff);
+  }
+
+  /**
+   * Reads an integer TLV.
+   *
+   * @return the integer value of the TLV
+   * @throws IllegalArgumentException if the next tlv is not an integer or is of unsupported length
+   */
+  public int readInt() throws IllegalArgumentException {
+    byte[] val = readPrimitive(TLV_INT);
+
+    switch (val.length) {
+      case 1:
+        return val[0] & 0xff;
+      case 2:
+        return ((val[0] & 0xff) << 8) | (val[1] & 0xff);
+      case 3:
+        return ((val[0] & 0xff) << 16) | ((val[1] & 0xff) << 8) | (val[2] & 0xff);
+      case 4:
+        return ((val[0] & 0xff) << 24) | ((val[1] & 0xff) << 16) | ((val[2] & 0xff) << 8) | (val[3] & 0xff);
+      default:
+        throw new IllegalArgumentException("Integers of length " + val.length + " are unsupported");
+    }
+  }
+
+  /**
+   * Low-level method to unread the last read tag. Only valid if the previous call was readTag(). Does nothing if the
+   * end of the TLV has been reached.
+   */
+  public void unreadLastTag() {
+    if (pos < buffer.length) {
+      pos--;
+    }
+  }
+
+  /**
+   * Reads the next tag. The current implementation only reads tags on one byte. Can be extended if needed.
+   *
+   * @return the tag
+   */
+  public int readTag() {
+    return (pos < buffer.length) ? buffer[pos++] : END_OF_TLV;
+  }
+
+  /**
+   * Reads the next tag. The current implementation only reads length on one and two bytes. Can be extended if needed.
+   *
+   * @return the tag
+   */
+  public int readLength() {
+    int len = buffer[pos++] & 0xff;
+
+    if (len == 0x81) {
+      len = buffer[pos++] & 0xff;
+    }
+
+    return len;
+  }
+
+  private void checkTag(int expected, int actual) throws IllegalArgumentException {
+    if (expected != actual) {
+      unreadLastTag();
+      throw new IllegalArgumentException("Expected tag: " + expected + ", received: " + actual);
+    }
+  }
+}

lib/src/main/java/im/status/keycard/globalplatform/Crypto.java

@@ -0,0 +1,229 @@
+package im.status.keycard.globalplatform;
+
+import org.bouncycastle.jce.provider.BouncyCastleProvider;
+
+import java.security.*;
+import java.util.Arrays;
+
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.spec.IvParameterSpec;
+import javax.crypto.spec.SecretKeySpec;
+
+/**
+ * Crypto utilities for Global Platform.
+ */
+public class Crypto {
+  public static final byte[] NullBytes8 = new byte[]{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+  public static long PIN_BOUND = 999999L;
+  public static long PUK_BOUND = 999999999999L;
+
+  private static boolean spongyCastleLoaded = false;
+
+  public static void addSpongyCastleProvider() {
+    if (!spongyCastleLoaded) {
+      Security.removeProvider(BouncyCastleProvider.PROVIDER_NAME);
+      Security.addProvider(new BouncyCastleProvider());
+      spongyCastleLoaded = true;
+    }
+  }
+
+  /**
+   * Derives a session key for SCP02.
+   *
+   * @param cardKey the key to derive
+   * @param seq the sequence number
+   * @param purposeData purpose data
+   *
+   * @return the derived key
+   */
+  public static byte[] deriveSCP02SessionKey(byte[] cardKey, byte[] seq, byte[] purposeData) {
+    byte[] key24 = resizeKey24(cardKey);
+
+    try {
+      byte[] derivationData = new byte[16];
+      // 2 bytes constant
+      System.arraycopy(purposeData, 0, derivationData, 0, 2);
+      // 2 bytes sequence counter + 12 bytes 0x00
+      System.arraycopy(seq, 0, derivationData, 2, 2);
+
+      SecretKeySpec tmpKey = new SecretKeySpec(key24, "DESede");
+
+      Cipher cipher = Cipher.getInstance("DESede/CBC/NoPadding", "BC");
+      cipher.init(Cipher.ENCRYPT_MODE, tmpKey, new IvParameterSpec(NullBytes8));
+
+      return cipher.doFinal(derivationData);
+    } catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
+      throw new IllegalStateException("error generating session keys.", e);
+    } catch (InvalidKeyException | IllegalBlockSizeException | BadPaddingException | InvalidAlgorithmParameterException e) {
+      throw new RuntimeException("error generating session keys.", e);
+    } catch (NoSuchProviderException e) {
+      throw new RuntimeException("SpongyCastle not installed");
+    }
+  }
+
+  /**
+   * Padding for SCP02 encryption.
+   *
+   * @param data data to pad
+   * @return the padded data
+   */
+  public static byte[] appendDESPadding(byte[] data) {
+    int paddingLength = 8 - (data.length % 8);
+    byte[] newData = new byte[data.length + paddingLength];
+    System.arraycopy(data, 0, newData, 0, data.length);
+    newData[data.length] = (byte)0x80;
+
+    return newData;
+  }
+
+  /**
+   * Verifies a card cryptogram received using during SCP02 channel establishment.
+   *
+   * @param key the key
+   * @param hostChallenge host challenge
+   * @param cardChallenge card challenge
+   * @param cardCryptogram cryptogram to verify
+   * @return true if correct, false otherwise
+   */
+  public static boolean verifyCryptogram(byte[] key, byte[] hostChallenge, byte[] cardChallenge, byte[] cardCryptogram) {
+    byte[] data = new byte[hostChallenge.length + cardChallenge.length];
+    System.arraycopy(hostChallenge, 0, data, 0, hostChallenge.length);
+    System.arraycopy(cardChallenge, 0, data, hostChallenge.length, cardChallenge.length);
+    byte[] paddedData = appendDESPadding(data);
+    byte[] calculated = mac3des(key, paddedData, NullBytes8);
+
+    return Arrays.equals(calculated , cardCryptogram);
+  }
+
+  /**
+   * Calculates a 3DES MAC for SCP02 channel establishment
+   *
+   * @param keyData key
+   * @param data data to sign
+   * @param iv IV
+   * @return the MAC
+   */
+  public static byte[] mac3des(byte[] keyData, byte[] data, byte[] iv) {
+    try {
+      SecretKeySpec key = new SecretKeySpec(resizeKey24(keyData), "DESede");
+      Cipher cipher = Cipher.getInstance("DESede/CBC/NoPadding", "BC");
+      cipher.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(iv));
+      byte[] result = cipher.doFinal(data, 0, 24);
+      byte[] tail = new byte[8];
+      System.arraycopy(result, 16, tail, 0, 8);
+      return tail;
+    } catch (GeneralSecurityException e) {
+      throw new RuntimeException("error calculating mac.", e);
+    }
+  }
+
+  /**
+   * Generates a 3DES MAC for SCP02 communication
+   *
+   * @param keyData key
+   * @param data data to sign
+   * @param iv IV
+   * @return the MAC
+   */
+  public static byte[] macFull3des(byte[] keyData, byte[] data, byte[] iv) {
+    try {
+      SecretKeySpec keyDes = new SecretKeySpec(resizeKey8(keyData), "DES");
+      Cipher cipherDes = Cipher.getInstance("DES/CBC/NoPadding", "BC");
+      cipherDes.init(Cipher.ENCRYPT_MODE, keyDes, new IvParameterSpec(iv));
+
+      SecretKeySpec keyDes3 = new SecretKeySpec(resizeKey24(keyData), "DESede");
+      Cipher cipherDes3 = Cipher.getInstance("DESede/CBC/NoPadding", "BC");
+      byte[] des3Iv = iv.clone();
+
+      if (data.length > 8) {
+        byte[] tmp = cipherDes.doFinal(data, 0, data.length - 8);
+        System.arraycopy(tmp, tmp.length - 8, des3Iv, 0, 8);
+      }
+
+      cipherDes3.init(Cipher.ENCRYPT_MODE, keyDes3, new IvParameterSpec(des3Iv));
+      byte[] result = cipherDes3.doFinal(data, data.length - 8, 8);
+      byte[] tail = new byte[8];
+      System.arraycopy(result, result.length - 8, tail, 0, 8);
+      return tail;
+    } catch (GeneralSecurityException e) {
+      throw new RuntimeException("error generating full triple DES MAC.", e);
+    }
+  }
+
+  /**
+   * Used during key derivation .
+   *
+   * @param keyData the key data
+   *
+   * @return the resized key
+   */
+  private static byte[] resizeKey24(byte[] keyData) {
+    byte[] key = new byte[24];
+    System.arraycopy(keyData, 0, key, 0, 16);
+    System.arraycopy(keyData, 0, key, 16, 8);
+
+    return key;
+  }
+
+  /**
+   * Used during MAC generation.
+   *
+   * @param keyData the key data
+   *
+   * @return the resized key
+   */
+  private static byte[] resizeKey8(byte[] keyData) {
+    byte[] key = new byte[8];
+    System.arraycopy(keyData, 0, key, 0, 8);
+
+    return key;
+  }
+
+  /**
+   * Encrypts the ICV
+   *
+   * @param macKeyData MAC Key
+   * @param mac mac
+   *
+   * @return encrypted ICV
+   */
+  public static byte[] encryptICV(byte[] macKeyData, byte[] mac) {
+    try {
+      Cipher cipher = Cipher.getInstance("DES/ECB/NoPadding", "BC");
+      SecretKeySpec key = new SecretKeySpec(resizeKey8(macKeyData), "DES");
+      cipher.init(Cipher.ENCRYPT_MODE, key);
+      return cipher.doFinal(mac);
+    } catch (GeneralSecurityException e) {
+      throw new RuntimeException("error generating ICV.", e);
+    }
+  }
+
+  /**
+   * Generates the given number of random bytes.
+   *
+   * @param length the number of bytes to generate
+   * @return random bytes
+   */
+  public static byte[] randomBytes(int length) {
+    SecureRandom random = new SecureRandom();
+    byte data[] = new byte[length];
+    random.nextBytes(data);
+
+    return data;
+  }
+
+  /**
+   * Generates a random long between 0 and then given boundary
+   *
+   * @param bound the maximum value to generate
+   * @return the random number
+   */
+  public static long randomLong(long bound) {
+    SecureRandom random = new SecureRandom();
+    return Math.abs(random.nextLong()) % bound;
+  }
+}

lib/src/main/java/im/status/keycard/globalplatform/GlobalPlatformCommandSet.java

@@ -0,0 +1,316 @@
+package im.status.keycard.globalplatform;
+
+import im.status.keycard.applet.Identifiers;
+import org.bouncycastle.util.encoders.Hex;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.security.SecureRandom;
+
+import im.status.keycard.io.APDUCommand;
+import im.status.keycard.io.APDUException;
+import im.status.keycard.io.APDUResponse;
+import im.status.keycard.io.CardChannel;
+
+/**
+ * Command set used for loading, installing and removing applets and packages. This class is generic and can work with
+ * any package and applet, but utility methods specific to the Keycard have been provided.
+ */
+public class GlobalPlatformCommandSet {
+  static final byte INS_SELECT = (byte) 0xA4;
+  static final byte INS_INITIALIZE_UPDATE = (byte) 0x50;
+  static final byte INS_EXTERNAL_AUTHENTICATE = (byte) 0x82;
+  static final byte INS_DELETE = (byte) 0xE4;
+  static final byte INS_INSTALL = (byte) 0xE6;
+  static final byte INS_LOAD = (byte) 0xE8;
+
+  static final byte SELECT_P1_BY_NAME = (byte) 0x04;
+  static final byte EXTERNAL_AUTHENTICATE_P1 = (byte) 0x01;
+  static final byte INSTALL_FOR_LOAD_P1 = (byte) 0x02;
+  static final byte INSTALL_FOR_INSTALL_P1 = (byte) 0x0C;
+  static final byte LOAD_P1_MORE_BLOCKS = (byte) 0x00;
+  static final byte LOAD_P1_LAST_BLOCK = (byte) 0x80;
+
+  private final CardChannel apduChannel;
+  private SecureChannel secureChannel;
+  private SCP02Keys cardKeys;
+  private Session session;
+
+  private final byte[] testKey = Hex.decode("404142434445464748494a4b4c4d4e4f");
+
+  /**
+   * Constructs a new command set with the given CardChannel.
+   *
+   * @param apduChannel the channel to the card
+   */
+  public GlobalPlatformCommandSet(CardChannel apduChannel) {
+    this.apduChannel = apduChannel;
+    this.cardKeys = new SCP02Keys(testKey, testKey);
+  }
+
+  /**
+   * Selects the ISD of the card.
+   *
+   * @return the card response
+   *
+   * @throws IOException communication error
+   */
+  public APDUResponse select() throws IOException {
+    APDUCommand cmd = new APDUCommand(0x00, INS_SELECT, SELECT_P1_BY_NAME, 0, new byte[0]);
+    return apduChannel.send(cmd);
+  }
+
+  /**
+   * Sends an INITIALIZE UPDATE command. Use the openSecureChannel method instead of calling this directly, unless you
+   * need to use a specific host challenge.
+   *
+   * @param hostChallenge the host challenge.
+   * @return the card response
+   *
+   * @throws IOException communication error
+   */
+  public APDUResponse initializeUpdate(byte[] hostChallenge) throws IOException, APDUException {
+    APDUCommand cmd = new APDUCommand(0x80, INS_INITIALIZE_UPDATE, 0, 0, hostChallenge, true);
+    APDUResponse resp = apduChannel.send(cmd);
+    if (resp.isOK()) {
+      this.session = SecureChannel.verifyChallenge(hostChallenge, this.cardKeys, resp);
+      this.secureChannel = new SecureChannel(this.apduChannel, this.session.getKeys());
+    }
+
+    return resp;
+  }
+
+  /**
+   * Sends an EXTERNAL AUTHENTICATE command. Use the openSecureChannel method instead of calling this directly, unless you
+   * need to use a specific host challenge.
+   *
+   * @param hostChallenge the host challenge.
+   * @return the card response
+   *
+   * @throws IOException communication error
+   */
+  public APDUResponse externalAuthenticate(byte[] hostChallenge) throws IOException {
+    byte[] cardChallenge = this.session.getCardChallenge();
+    byte[] data = new byte[cardChallenge.length + hostChallenge.length];
+    System.arraycopy(cardChallenge, 0, data, 0, cardChallenge.length);
+    System.arraycopy(hostChallenge, 0, data, cardChallenge.length, hostChallenge.length);
+
+    byte[] paddedData = Crypto.appendDESPadding(data);
+    byte[] hostCryptogram = Crypto.mac3des(this.session.getKeys().encKeyData, paddedData, Crypto.NullBytes8);
+
+    APDUCommand cmd = new APDUCommand(0x84, INS_EXTERNAL_AUTHENTICATE, EXTERNAL_AUTHENTICATE_P1, 0, hostCryptogram);
+    return this.secureChannel.send(cmd);
+  }
+
+  /**
+   * Opens an SCP02 secure channel with default keys.
+   *
+   * @throws APDUException the card didn't respond 0x9000 to either INITIALIZE UPDATE or EXTERNAL AUTHENTICATE
+   * @throws IOException communication error
+   */
+  public void openSecureChannel() throws APDUException, IOException {
+    SecureRandom random = new SecureRandom();
+    byte[] hostChallenge = new byte[8];
+    random.nextBytes(hostChallenge);
+    initializeUpdate(hostChallenge).checkOK();
+    externalAuthenticate(hostChallenge).checkOK();
+  }
+
+  /**
+   * Deletes the Keycard applet instance.
+   *
+   * @return the card response
+   * @throws IOException communication error
+   */
+  public APDUResponse deleteKeycardInstance() throws IOException {
+    return delete(Identifiers.getKeycardInstanceAID());
+  }
+
+  /**
+   * Deletes the NDEF applet instance.
+   *
+   * @return the card response
+   * @throws IOException communication error
+   */
+  public APDUResponse deleteNDEFInstance() throws IOException {
+    return delete(Identifiers.NDEF_INSTANCE_AID);
+  }
+
+  /**
+   * Deletes the Keycard package.
+   *
+   * @return the card response
+   * @throws IOException communication error
+   */
+  public APDUResponse deleteKeycardPackage() throws IOException {
+    return delete(Identifiers.PACKAGE_AID);
+  }
+
+  /**
+   * Deletes the Keycard package and all applets installed from it. This is the method to use to remove a Keycard
+   * installation.
+   *
+   * @throws APDUException one of the DELETE commands failed
+   * @throws IOException communication error
+   */
+  public void deleteKeycardInstancesAndPackage() throws IOException, APDUException {
+    deleteNDEFInstance().checkSW(APDUResponse.SW_OK, APDUResponse.SW_REFERENCED_DATA_NOT_FOUND);
+    deleteKeycardInstance().checkSW(APDUResponse.SW_OK, APDUResponse.SW_REFERENCED_DATA_NOT_FOUND);
+    deleteKeycardPackage().checkSW(APDUResponse.SW_OK, APDUResponse.SW_REFERENCED_DATA_NOT_FOUND);
+  }
+
+  /**
+   * Sends a DELETE APDU with the given AID
+   * @param aid the AID to the delete
+   * @return the raw card response
+   *
+   * @throws IOException communication error.
+   */
+  public APDUResponse delete(byte[] aid) throws IOException {
+    byte[] data = new byte[aid.length + 2];
+    data[0] = 0x4F;
+    data[1] = (byte) aid.length;
+    System.arraycopy(aid, 0, data, 2, aid.length);
+
+    APDUCommand cmd = new APDUCommand(0x80, INS_DELETE, 0, 0, data);
+
+    return this.secureChannel.send(cmd);
+  }
+
+  /**
+   * Loads the Keycard package.
+   *
+   * @param in the CAP file as an InputStream
+   * @param cb the progress callback
+   *
+   * @throws IOException communication error
+   * @throws APDUException one of the INSTALL [for Load] or LOAD commands failed
+   */
+  public void loadKeycardPackage(InputStream in, LoadCallback cb) throws IOException, APDUException {
+    installForLoad(Identifiers.PACKAGE_AID).checkOK();
+
+    Load load = new Load(in);
+
+    byte[] block;
+    int steps = load.blocksCount();
+
+    while((block = load.nextDataBlock()) != null) {
+      load(block, (load.getCount() - 1), load.hasMore()).checkOK();
+      cb.blockLoaded(load.getCount(), steps);
+    }
+  }
+
+  /**
+   * Sends an INSTALL [for LOAD] APDU. Use only if loading something other than the Keycard package.
+   *
+   * @param aid the AID
+   *
+   * @return the card response
+   * @throws IOException communication error
+   */
+  public APDUResponse installForLoad(byte[] aid) throws IOException {
+    return installForLoad(aid, new byte[0]);
+  }
+
+  /**
+   * Sends an INSTALL [for LOAD] APDU with package extradition. Use only if loading something other than the Keycard package.
+   *
+   * @param aid the AID
+   * @param sdaid the AID of the SD target of the extradition
+   *
+   * @return the card response
+   * @throws IOException communication error
+   */
+  public APDUResponse installForLoad(byte[] aid, byte[] sdaid) throws IOException {
+    ByteArrayOutputStream data = new ByteArrayOutputStream();
+    data.write(aid.length);
+    data.write(aid);
+    data.write(sdaid.length);
+    data.write(sdaid);
+
+    // empty hash length and hash
+    data.write(0x00);
+    data.write(0x00);
+    data.write(0x00);
+
+    APDUCommand cmd = new APDUCommand(0x80, INS_INSTALL, INSTALL_FOR_LOAD_P1, 0, data.toByteArray());
+
+    return this.secureChannel.send(cmd);
+  }
+
+  /**
+   * Sends a single LOAD APDU. Use only if loading something other than the Keycard package.
+   *
+   * @param data the data of the block
+   * @param count the block number
+   * @param hasMoreBlocks whether there are more blocks coming or not
+   * @return the card response
+   * @throws IOException communication error
+   */
+  public APDUResponse load(byte[] data, int count, boolean hasMoreBlocks) throws IOException {
+    int p1 = hasMoreBlocks ? LOAD_P1_MORE_BLOCKS : LOAD_P1_LAST_BLOCK;
+    APDUCommand cmd = new APDUCommand(0x80, INS_LOAD, p1, count, data);
+    return this.secureChannel.send(cmd);
+  }
+
+  /**
+   * Sends an INSTALL [for Install & Make Selectable] command. Use only if not installing applets part of the Keycard
+   * package
+   *
+   * @param packageAID the package AID
+   * @param appletAID the applet AID
+   * @param instanceAID the instance AID
+   * @param params the installation parameters
+   * @return the card response
+   * @throws IOException communication error
+   */
+  public APDUResponse installForInstall(byte[] packageAID, byte[] appletAID, byte[] instanceAID, byte[] params) throws IOException {
+    ByteArrayOutputStream data = new ByteArrayOutputStream();
+    data.write(packageAID.length);
+    data.write(packageAID);
+    data.write(appletAID.length);
+    data.write(appletAID);
+    data.write(instanceAID.length);
+    data.write(instanceAID);
+
+    byte[] privileges = new byte[]{0x00};
+    data.write(privileges.length);
+    data.write(privileges);
+
+    byte[] fullParams = new byte[2 + params.length];
+    fullParams[0] = (byte) 0xC9;
+    fullParams[1] = (byte) params.length;
+    System.arraycopy(params, 0, fullParams, 2, params.length);
+
+    data.write(fullParams.length);
+    data.write(fullParams);
+
+    // empty perform token
+    data.write(0x00);
+    APDUCommand cmd = new APDUCommand(0x80, INS_INSTALL, INSTALL_FOR_INSTALL_P1, 0, data.toByteArray());
+
+    return this.secureChannel.send(cmd);
+  }
+
+  /**
+   * Installs the NDEF applet from the Keycard package.
+   *
+   * @param ndefRecord the initial NDEF record. Can be a zero-length array but not null
+   * @return the card response
+   * @throws IOException communication error
+   */
+  public APDUResponse installNDEFApplet(byte[] ndefRecord) throws IOException {
+    return installForInstall(Identifiers.PACKAGE_AID, Identifiers.NDEF_AID, Identifiers.NDEF_INSTANCE_AID, ndefRecord);
+  }
+
+  /**
+   * Installs the Keycard applet.
+   *
+   * @return the card response
+   * @throws IOException communication error.
+   */
+  public APDUResponse installKeycardApplet() throws IOException {
+    return installForInstall(Identifiers.PACKAGE_AID, Identifiers.KEYCARD_AID, Identifiers.getKeycardInstanceAID(), new byte[0]);
+  }
+}

lib/src/main/java/im/status/keycard/globalplatform/Load.java

@@ -0,0 +1,189 @@
+package im.status.keycard.globalplatform;
+
+import java.io.ByteArrayOutputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
+
+/**
+ * A loadable CAP file.
+ */
+public class Load {
+  static final byte CLA = (byte) 0x80;
+  static final byte INS = (byte) 0xE8;
+
+  static final int BLOCK_SIZE = 247; // 255 - 8 bytes for MAC
+
+  private static String[] fileNames = {"Header", "Directory", "Import", "Applet",
+      "Class", "Method", "StaticField", "Export", "ConstantPool", "RefLocation"};
+
+  private int offset;
+  private int count;
+  private byte[] fullData;
+
+  /**
+   * Reads a CAP file from the given input stream.
+   *
+   * @param in the inpu stream
+   * @throws FileNotFoundException
+   * @throws IOException
+   */
+  public Load(InputStream in) throws FileNotFoundException, IOException {
+    this.offset = 0;
+    this.count = 0;
+    Map<String, byte[]> files = this.loadFiles(in);
+    in.close();
+    this.fullData = this.getCode(files);
+  }
+
+  /**
+   * Reads the components of the CAP file
+   * @param in the input stream
+   * @return the map of component name and values
+   *
+   * @throws IOException IO error
+   */
+  private Map<String, byte[]> loadFiles(InputStream in) throws IOException {
+    Map<String, byte[]> files = new LinkedHashMap<>();
+    ZipInputStream zip = new ZipInputStream(in);
+    ZipEntry entry = zip.getNextEntry();
+
+    while (entry != null) {
+      ByteArrayOutputStream data = new ByteArrayOutputStream();
+      byte[] buf = new byte[1024];
+      int count;
+      while ((count = zip.read(buf)) != -1) {
+        data.write(buf, 0, count);
+      }
+      String name = baseName(entry.getName());
+      files.put(name, data.toByteArray());
+      entry = zip.getNextEntry();
+    }
+
+    return files;
+  }
+
+  /**
+   * The basename of the zip entry
+   * @param path the path
+   * @return the base name
+   */
+  private String baseName(String path) {
+    String[] parts = path.split("[/.]");
+    return parts[parts.length - 2];
+  }
+
+  /**
+   * Counts the number of blocks needed to load the entire file. Keeps in account the overhead of SCP02 secure channel
+   *
+   * @return the block count
+   */
+  public int blocksCount() {
+    return (int) Math.ceil(this.fullData.length / (float) BLOCK_SIZE);
+  }
+
+  /**
+   * Returns the next data block
+   *
+   * @return the data block
+   */
+  public byte[] nextDataBlock() {
+    if (this.offset >= this.fullData.length) {
+      return null;
+    }
+
+    int rangeEnd = this.offset + BLOCK_SIZE;
+    if (rangeEnd >= this.fullData.length) {
+      rangeEnd = this.fullData.length;
+    }
+
+    int size = rangeEnd - offset;
+    byte[] data = new byte[size];
+    System.arraycopy(this.fullData, this.offset, data, 0, size);
+
+
+    this.count++;
+    this.offset += size;
+
+    return data;
+  }
+
+  /**
+   * True if more blocks are present, false otherwise.
+   *
+   * @return true if more blocks are present, false otherwise.
+   */
+  public boolean hasMore() {
+    return this.offset < this.fullData.length;
+  }
+
+  /**
+   * Encodes the length of the load TLV component
+   *
+   * @param length the length as integer
+   * @return the length encoded as for BER-TLV
+   */
+  private byte[] encodeFullLength(int length) {
+    if (length < 0x80) {
+      return new byte[]{(byte) length};
+    } else if (length < 0xFF) {
+      return new byte[]{(byte) 0x81, (byte) length};
+    } else if (length < 0xFFFF) {
+      return new byte[]{
+          (byte) 0x82,
+          (byte) ((length & 0xFF00) >> 8),
+          (byte) (length & 0xFF),
+      };
+    } else {
+      return new byte[]{
+          (byte) 0x83,
+          (byte) ((length & 0xFF0000) >> 16),
+          (byte) ((length & 0xFF00) >> 8),
+          (byte) (length & 0xFF),
+      };
+    }
+  }
+
+  /**
+   * Serializes the CAP section in a single block.
+   *
+   * @param files the components to serialize
+   * @return the serialized load file
+   *
+   */
+  private byte[] getCode(Map<String, byte[]> files) throws IOException {
+    ByteArrayOutputStream dataStream = new ByteArrayOutputStream();
+
+    for (String name : fileNames) {
+      byte[] fileData = files.get(name);
+      if (fileData == null) {
+        continue;
+      }
+
+      dataStream.write(fileData);
+    }
+
+    byte[] data = dataStream.toByteArray();
+    byte[] encodedFullLength = encodeFullLength(data.length);
+    byte[] fullData = new byte[1 + encodedFullLength.length + data.length];
+
+    fullData[0] = (byte) 0xC4;
+    System.arraycopy(encodedFullLength, 0, fullData, 1, encodedFullLength.length);
+    System.arraycopy(data, 0, fullData, 1 + encodedFullLength.length, data.length);
+
+    return fullData;
+  }
+
+  /**
+   * Returns the current block number
+   *
+   * @return the current block number
+   */
+  public int getCount() {
+    return count;
+  }
+}

lib/src/main/java/im/status/keycard/globalplatform/LoadCallback.java

@@ -0,0 +1,14 @@
+package im.status.keycard.globalplatform;
+
+/**
+ * Callback interface using during package loading process.
+ */
+public interface LoadCallback {
+  /**
+   * Called when a block is loaded.
+   *
+   * @param loadedBlock The number of the loaded block (1 based)
+   * @param blockCount the total number of blocks.
+   */
+  void blockLoaded(int loadedBlock, int blockCount);
+}

lib/src/main/java/im/status/keycard/globalplatform/SCP02Keys.java

@@ -0,0 +1,37 @@
+package im.status.keycard.globalplatform;
+
+/**
+ * Keeps keys for SCP02.
+ */
+public class SCP02Keys {
+  public byte[] encKeyData;
+  public byte[] macKeyData;
+
+  /**
+   * Constructor. Takes the ENC and MAC keys.
+   *
+   * @param encKeyData encryption key
+   * @param macKeyData mac key
+   */
+  public SCP02Keys(byte[] encKeyData, byte[] macKeyData) {
+    this.encKeyData = encKeyData;
+    this.macKeyData = macKeyData;
+  }
+
+  /**
+   * The encryption key
+   * @return the encryption key
+   */
+  public byte[] getEncKeyData() {
+    return encKeyData;
+  }
+
+  /**
+   * The MAC key
+   *
+   * @return the MAC key
+   */
+  public byte[] getMacKeyData() {
+    return macKeyData;
+  }
+}

lib/src/main/java/im/status/keycard/globalplatform/SCP02Wrapper.java

@@ -0,0 +1,73 @@
+package im.status.keycard.globalplatform;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.Arrays;
+
+import im.status.keycard.io.APDUCommand;
+
+/**
+ * Adds a SCP02 MAC to APDUs.
+ */
+public class SCP02Wrapper {
+  private byte[] macKeyData;
+  private byte[] icv;
+
+  /**
+   * Constructs a new SCP02Wrapper.
+   *
+   * @param macKeyData the MAC key
+   */
+  public SCP02Wrapper(byte[] macKeyData) {
+    this.macKeyData = macKeyData;
+    this.icv = Crypto.NullBytes8.clone();
+  }
+
+  /**
+   * Wraps an APDU with SCP02 MAC
+   * @param cmd the APDU to wrap
+   * @return the wrapped APDU
+   */
+  public APDUCommand wrap(APDUCommand cmd) {
+    try {
+      int cla = (cmd.getCla() | 0x04) & 0xff;
+      byte[] data = cmd.getData();
+
+      ByteArrayOutputStream macData = new ByteArrayOutputStream();
+      macData.write(cla);
+      macData.write(cmd.getIns());
+      macData.write(cmd.getP1());
+      macData.write(cmd.getP2());
+      macData.write(data.length + 8);
+      macData.write(data);
+
+      byte[] icv;
+      if (Arrays.equals(this.icv, Crypto.NullBytes8)) {
+        icv = this.icv;
+      } else {
+        icv = Crypto.encryptICV(this.macKeyData, this.icv);
+      }
+
+      byte[] mac = Crypto.macFull3des(this.macKeyData, Crypto.appendDESPadding(macData.toByteArray()), icv);
+      byte[] newData = new byte[data.length + mac.length];
+      System.arraycopy(data, 0, newData, 0, data.length );
+      System.arraycopy(mac, 0, newData, data.length, mac.length );
+
+      APDUCommand wrapped = new APDUCommand(cla, cmd.getIns(), cmd.getP1(), cmd.getP2(), newData, cmd.getNeedsLE());
+      this.icv = mac.clone();
+
+      return wrapped;
+    } catch (IOException e) {
+      throw new RuntimeException("error wrapping APDU command.", e);
+    }
+  }
+
+  /**
+   * Returns the ICV
+   * @return the ICV
+   */
+  public byte[] getICV() {
+    return this.icv;
+  }
+}
+

lib/src/main/java/im/status/keycard/globalplatform/SecureChannel.java

@@ -0,0 +1,90 @@
+package im.status.keycard.globalplatform;
+
+import java.io.IOException;
+
+import im.status.keycard.io.APDUCommand;
+import im.status.keycard.io.APDUException;
+import im.status.keycard.io.APDUResponse;
+import im.status.keycard.io.CardChannel;
+
+/**
+ * An SCP02 Secure Channel. Wraps a CardChannel to allow transparent handling of the scure channel.
+ */
+public class SecureChannel {
+  private CardChannel channel;
+  private SCP02Wrapper wrapper;
+
+  public static byte[] DERIVATION_PURPOSE_ENC = new byte[]{(byte) 0x01, (byte) 0x82};
+  public static byte[] DERIVATION_PURPOSE_MAC = new byte[]{(byte) 0x01, (byte) 0x01};
+  public static byte[] DERIVATION_PURPOSE_DEK = new byte[]{(byte) 0x01, (byte) 0x81};
+
+  /**
+   * Constructs an SCP02 secure channel, wrapping a regular CardChannel.
+   *
+   * @param channel the channel to wrap
+   * @param keys the keys
+   */
+  public SecureChannel(CardChannel channel, SCP02Keys keys) {
+    this.channel = channel;
+    this.wrapper = new SCP02Wrapper(keys.getMacKeyData());
+  }
+
+  /**
+   * Protects the given command with SCP02 and forwards it to the underlying CardChannel.
+   *
+   * @param cmd the command to send
+   * @return the response from the card
+   *
+   * @throws IOException communication error
+   */
+  public APDUResponse send(APDUCommand cmd) throws IOException {
+    APDUCommand wrappedCommand = this.wrapper.wrap(cmd);
+    return this.channel.send(wrappedCommand);
+  }
+
+  /**
+   * Verifies the card challenge and builds an SCP02 session object.
+   *
+   * @param hostChallenge the host challenge
+   * @param cardKeys the SCP02 keys
+   * @param resp the response from the card to the INITIALIZE UPDATE oommand
+   * @return the Session object built on succesful verification
+   * @throws APDUException communication error
+   */
+  public static Session verifyChallenge(byte[] hostChallenge, SCP02Keys cardKeys, APDUResponse resp) throws APDUException {
+    if (resp.getSw() == APDUResponse.SW_SECURITY_CONDITION_NOT_SATISFIED) {
+      throw new APDUException(resp.getSw(), "security condition not satisfied");
+    }
+
+    if (resp.getSw() == APDUResponse.SW_AUTHENTICATION_METHOD_BLOCKED) {
+      throw new APDUException(resp.getSw(), "authentication method blocked");
+    }
+
+    byte[] data = resp.getData();
+
+    if (data.length != 28) {
+      throw new APDUException(resp.getSw(), String.format("bad data length, expected 28, got %d", data.length));
+    }
+
+    byte[] cardChallenge = new byte[8];
+    System.arraycopy(data, 12, cardChallenge, 0, 8);
+
+    byte[] cardCryptogram = new byte[8];
+    System.arraycopy(data, 20, cardCryptogram, 0, 8);
+
+    byte[] seq = new byte[2];
+    System.arraycopy(data, 12, seq, 0, 2);
+
+    byte[] sessionEncKey = Crypto.deriveSCP02SessionKey(cardKeys.getEncKeyData(), seq, DERIVATION_PURPOSE_ENC);
+    byte[] sessionMacKey = Crypto.deriveSCP02SessionKey(cardKeys.getMacKeyData(), seq, DERIVATION_PURPOSE_MAC);
+
+    SCP02Keys sessionKeys = new SCP02Keys(sessionEncKey, sessionMacKey);
+
+    boolean verified = Crypto.verifyCryptogram(sessionKeys.getEncKeyData(), hostChallenge, cardChallenge, cardCryptogram);
+    if (!verified) {
+      throw new APDUException("error verifying card cryptogram.");
+    }
+
+    return new Session(sessionKeys, cardChallenge);
+  }
+}

lib/src/main/java/im/status/keycard/globalplatform/Session.java

@@ -0,0 +1,36 @@
+package im.status.keycard.globalplatform;
+
+/**
+ * SCP02 Session.
+ */
+public class Session {
+  private SCP02Keys keys;
+  private byte[] cardChallenge;
+
+  /**
+   * Constructs the SCP02 session.
+   *
+   * @param keys the session keys
+   * @param cardChallenge the card challenge
+   */
+  public Session(SCP02Keys keys, byte[] cardChallenge) {
+    this.keys = keys;
+    this.cardChallenge = cardChallenge;
+  }
+
+  /**
+   * The SCP02 keys
+   * @return SCP02 keys
+   */
+  public SCP02Keys getKeys() {
+    return keys;
+  }
+
+  /**
+   * The card challenge
+   * @return card challenge
+   */
+  public byte[] getCardChallenge() {
+    return cardChallenge;
+  }
+}

lib/src/main/java/im/status/keycard/io/APDUCommand.java

@@ -0,0 +1,125 @@
+package im.status.keycard.io;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+
+/**
+ * ISO7816-4 APDU.
+ */
+public class APDUCommand {
+  protected int cla;
+  protected int ins;
+  protected int p1;
+  protected int p2;
+  protected int lc;
+  protected byte[] data;
+  protected boolean needsLE;
+
+  /**
+   * Constructs an APDU with no response data length field. The data field cannot be null, but can be a zero-length array.
+   *
+   * @param cla class byte
+   * @param ins instruction code
+   * @param p1 P1 parameter
+   * @param p2 P2 parameter
+   * @param data the APDU data
+   */
+  public APDUCommand(int cla, int ins, int p1, int p2, byte[] data) {
+    this(cla, ins, p1, p2, data, false);
+  }
+
+  /**
+   * Constructs an APDU with an optional data length field. The data field cannot be null, but can be a zero-length array.
+   * The LE byte, if sent, is set to 0.
+   *
+   * @param cla class byte
+   * @param ins instruction code
+   * @param p1 P1 parameter
+   * @param p2 P2 parameter
+   * @param data the APDU data
+   * @param needsLE whether the LE byte should be sent or not
+   */
+  public APDUCommand(int cla, int ins, int p1, int p2, byte[] data, boolean needsLE) {
+    this.cla = cla & 0xff;
+    this.ins = ins & 0xff;
+    this.p1 = p1 & 0xff;
+    this.p2 = p2 & 0xff;
+    this.data = data;
+    this.needsLE = needsLE;
+  }
+
+  /**
+   * Serializes the APDU in order to send it to the card.
+   *
+   * @return the byte array representation of the APDU
+   */
+  public byte[] serialize() throws IOException {
+    ByteArrayOutputStream out = new ByteArrayOutputStream();
+    out.write(this.cla);
+    out.write(this.ins);
+    out.write(this.p1);
+    out.write(this.p2);
+    out.write(this.data.length);
+    out.write(this.data);
+
+    if (this.needsLE) {
+      out.write(0); // Response length
+    }
+
+    return out.toByteArray();
+  }
+
+  /**
+   * Returns the CLA of the APDU
+   *
+   * @return the CLA of the APDU
+   */
+  public int getCla() {
+    return cla;
+  }
+
+  /**
+   * Returns the INS of the APDU
+   *
+   * @return the INS of the APDU
+   */
+  public int getIns() {
+    return ins;
+  }
+
+  /**
+   * Returns the P1 of the APDU
+   *
+   * @return the P1 of the APDU
+   */
+  public int getP1() {
+    return p1;
+  }
+
+  /**
+   * Returns the P2 of the APDU
+   *
+   * @return the P2 of the APDU
+   */
+  public int getP2() {
+    return p2;
+  }
+
+  /**
+   * Returns the data field of the APDU
+   *
+   * @return the data field of the APDU
+   */
+  public byte[] getData() {
+    return data;
+  }
+
+  /**
+   * Returns whether LE is sent or not.
+   *
+   * @return whether LE is sent or not
+   */
+  public boolean getNeedsLE() {
+    return this.needsLE;
+  }
+}

lib/src/main/java/im/status/keycard/io/APDUException.java

@@ -0,0 +1,29 @@
+package im.status.keycard.io;
+
+/**
+ * Exception thrown when the response APDU from the card contains unexpected SW or data.
+ */
+public class APDUException extends Exception {
+  public final int sw;
+
+  /**
+   * Creates an exception with SW and message.
+   *
+   * @param sw the status word
+   * @param message a descriptive message of the error
+   */
+  public APDUException(int sw, String message) {
+    super(message + ", 0x" + String.format("%04X", sw));
+    this.sw = sw;
+  }
+
+  /**
+   * Creates an exception with a message.
+   *
+   * @param message a descriptive message of the error
+   */
+  public APDUException(String message) {
+    super(message);
+    this.sw = 0;
+  }
+}

lib/src/main/java/im/status/keycard/io/APDUResponse.java

@@ -0,0 +1,132 @@
+package im.status.keycard.io;
+
+/**
+ * ISO7816-4 APDU response.
+ */
+public class APDUResponse {
+  public static final int SW_OK = 0x9000;
+  public static final int SW_SECURITY_CONDITION_NOT_SATISFIED = 0x6982;
+  public static final int SW_AUTHENTICATION_METHOD_BLOCKED = 0x6983;
+  public static final int SW_CARD_LOCKED = 0x6283;
+  public static final int SW_REFERENCED_DATA_NOT_FOUND = 0x6A88;
+  public static final int SW_CONDITIONS_OF_USE_NOT_SATISFIED = 0x6985; // applet may be already installed
+
+  private byte[] apdu;
+  private byte[] data;
+  private int sw;
+  private int sw1;
+  private int sw2;
+
+  /**
+   * Creates an APDU object by parsing the raw response from the card.
+   *
+   * @param apdu the raw response from the card.
+   */
+  public APDUResponse(byte[] apdu)  {
+    if (apdu.length < 2) {
+      throw new IllegalArgumentException("APDU response must be at least 2 bytes");
+    }
+    this.apdu = apdu;
+    this.parse();
+  }
+
+  /**
+   * Parses the APDU response, separating the response data from SW.
+   */
+  private void parse() {
+    int length = this.apdu.length;
+
+    this.sw1 = this.apdu[length - 2] & 0xff;
+    this.sw2 = this.apdu[length - 1] & 0xff;
+    this.sw = (this.sw1 << 8) | this.sw2;
+
+    this.data = new byte[length - 2];
+    System.arraycopy(this.apdu, 0, this.data, 0, length - 2);
+  }
+
+  /**
+   * Returns true if the SW is 0x9000.
+   *
+   * @return true if the SW is 0x9000.
+   */
+  public boolean isOK() {
+    return this.sw == SW_OK;
+  }
+
+  /**
+   * Asserts that the SW is 0x9000. Throws an exception if it isn't
+   *
+   * @return this object, to simplify chaining
+   * @throws APDUException if the SW is not 0x9000
+   */
+  public APDUResponse checkOK() throws APDUException {
+    return this.checkSW(SW_OK);
+  }
+
+  /**
+   * Asserts that the SW is contained in the given list. Throws an exception if it isn't.
+   *
+   * @param codes the list of SWs to match.
+   * @return this object, to simplify chaining
+   * @throws APDUException if the SW is not 0x9000
+   */
+  public APDUResponse checkSW(int... codes) throws APDUException {
+    for (int code : codes) {
+      if (this.sw == code) {
+        return this;
+      }
+    }
+
+    switch (this.sw) {
+      case SW_SECURITY_CONDITION_NOT_SATISFIED:
+        throw new APDUException(this.sw, "security condition not satisfied");
+      case SW_AUTHENTICATION_METHOD_BLOCKED:
+        throw new APDUException(this.sw, "authentication method blocked");
+      default:
+        throw new APDUException(this.sw,  "Unexpected error SW");
+    }
+  }
+
+  /**
+   * Returns the data field of this APDU.
+   *
+   * @return the data field of this APDU
+   */
+  public byte[] getData() {
+    return this.data;
+  }
+
+  /**
+   * Returns the Status Word.
+   *
+   * @return the status word
+   */
+  public int getSw() {
+    return this.sw;
+  }
+
+  /**
+   * Returns the SW1 byte
+   * @return SW1
+   */
+  public int getSw1() {
+    return this.sw1;
+  }
+
+  /**
+   * Returns the SW2 byte
+   * @return SW2
+   */
+  public int getSw2() {
+    return this.sw2;
+  }
+
+  /**
+   * Returns the raw unparsed response.
+   *
+   * @return raw APDU data
+   */
+  public byte[] getBytes() {
+    return this.apdu;
+  }
+}

lib/src/main/java/im/status/keycard/io/CardChannel.java

@@ -0,0 +1,23 @@
+package im.status.keycard.io;
+
+import java.io.IOException;
+
+/**
+ * A channel to transcieve ISO7816-4 APDUs.
+ */
+public interface CardChannel {
+  /**
+   * Sends the given C-APDU and returns an R-APDU.
+   *
+   * @param cmd the command to send
+   * @return the card response
+   * @throws IOException communication error
+   */
+  APDUResponse send(APDUCommand cmd) throws IOException;
+
+  /**
+   * True if connected, false otherwise
+   * @return true if connected, false otherwise
+   */
+  boolean isConnected();
+}

lib/src/main/java/im/status/keycard/io/CardListener.java

@@ -0,0 +1,18 @@
+package im.status.keycard.io;
+
+/**
+ * Listener for card connection events.
+ */
+public interface CardListener {
+  /**
+   * Executes when the card channel is connected.
+   *
+   * @param channel the connected card channel
+   */
+  void onConnected(CardChannel channel);
+
+  /**
+   * Executes when a previously connected card is disconnected.
+   */
+  void onDisconnected();
+}

settings.gradle

@@ -1,2 +1,4 @@
-include ':lib'
-include ':demo'
+include 'lib'
+include 'android'
+include 'desktop'
+include 'demo-android'