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implement AES CBC-MAC with a software fallback

This commit is contained in:
Michele Balistreri 2017-11-21 16:21:56 +03:00
parent 9cab2f993a
commit e04f4c7bc7
1 changed files with 35 additions and 10 deletions
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31
src/main/java/im/status/wallet/SecureChannel.java
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@ -22,9 +22,13 @@ public class SecureChannel {
public static final byte PAIR_P1_FIRST_STEP = 0x00; public static final byte PAIR_P1_FIRST_STEP = 0x00;
public static final byte PAIR_P1_LAST_STEP = 0x01; public static final byte PAIR_P1_LAST_STEP = 0x01;
public static final short MAX_MAC_APDU_SIZE = (short) 256;
private AESKey scEncKey; private AESKey scEncKey;
private AESKey scMacKey; private AESKey scMacKey;
private Cipher scCipher; private Cipher scCipher;
private Cipher scMacCipher;
private byte[] macCipherBuf;
private Signature scMac; private Signature scMac;
private KeyPair scKeypair; private KeyPair scKeypair;
private byte[] secret; private byte[] secret;
@ -46,7 +50,12 @@ public class SecureChannel {
public SecureChannel(byte pairingLimit, byte[] aPairingSecret, short off) { public SecureChannel(byte pairingLimit, byte[] aPairingSecret, short off) {
scCipher = Cipher.getInstance(Cipher.ALG_AES_CBC_ISO9797_M2,false); scCipher = Cipher.getInstance(Cipher.ALG_AES_CBC_ISO9797_M2,false);
try {
scMac = Signature.getInstance(Signature.ALG_AES_MAC_128_NOPAD, false); scMac = Signature.getInstance(Signature.ALG_AES_MAC_128_NOPAD, false);
} catch (CryptoException e) {
scMacCipher = Cipher.getInstance(Cipher.ALG_AES_BLOCK_128_CBC_NOPAD, false);
macCipherBuf = JCSystem.makeTransientByteArray(MAX_MAC_APDU_SIZE, JCSystem.CLEAR_ON_DESELECT);
}
scEncKey = (AESKey) KeyBuilder.buildKey(KeyBuilder.TYPE_AES_TRANSIENT_DESELECT, KeyBuilder.LENGTH_AES_256, false); scEncKey = (AESKey) KeyBuilder.buildKey(KeyBuilder.TYPE_AES_TRANSIENT_DESELECT, KeyBuilder.LENGTH_AES_256, false);
scMacKey = (AESKey) KeyBuilder.buildKey(KeyBuilder.TYPE_AES_TRANSIENT_DESELECT, KeyBuilder.LENGTH_AES_256, false); scMacKey = (AESKey) KeyBuilder.buildKey(KeyBuilder.TYPE_AES_TRANSIENT_DESELECT, KeyBuilder.LENGTH_AES_256, false);
@ -56,7 +65,7 @@ public class SecureChannel {
SECP256k1.setCurveParameters((ECKey) scKeypair.getPublic()); SECP256k1.setCurveParameters((ECKey) scKeypair.getPublic());
scKeypair.genKeyPair(); scKeypair.genKeyPair();
secret = JCSystem.makeTransientByteArray((byte)(SC_SECRET_LENGTH * 2), JCSystem.CLEAR_ON_DESELECT); secret = JCSystem.makeTransientByteArray((short)(SC_SECRET_LENGTH * 2), JCSystem.CLEAR_ON_DESELECT);
pairingSecret = new byte[SC_SECRET_LENGTH]; pairingSecret = new byte[SC_SECRET_LENGTH];
pairingKeys = new byte[(short)(PAIRING_KEY_LENGTH * pairingLimit)]; pairingKeys = new byte[(short)(PAIRING_KEY_LENGTH * pairingLimit)];
@ -261,12 +270,20 @@ public class SecureChannel {
} }
public boolean verifyAESMAC(byte[] apduBuffer, short apduLen) { public boolean verifyAESMAC(byte[] apduBuffer, short apduLen) {
if (scMac == null) {
scMacCipher.init(scMacKey, Cipher.MODE_ENCRYPT);
short encLen = scMacCipher.update(apduBuffer, (short) 0, ISO7816.OFFSET_CDATA, macCipherBuf, (short) 0);
encLen += scMacCipher.update(secret, SC_BLOCK_SIZE, (short) (SC_BLOCK_SIZE - ISO7816.OFFSET_CDATA), macCipherBuf, encLen);
encLen += scMacCipher.doFinal(apduBuffer, (short) (ISO7816.OFFSET_CDATA + SC_BLOCK_SIZE), (short) (apduLen - SC_BLOCK_SIZE), macCipherBuf, encLen);
return Util.arrayCompare(apduBuffer, ISO7816.OFFSET_CDATA, macCipherBuf, (short)(encLen - SC_BLOCK_SIZE), SC_BLOCK_SIZE) == 0;
} else {
scMac.init(scMacKey, Signature.MODE_VERIFY); scMac.init(scMacKey, Signature.MODE_VERIFY);
scMac.update(apduBuffer, (short) 0, ISO7816.OFFSET_CDATA); scMac.update(apduBuffer, (short) 0, ISO7816.OFFSET_CDATA);
scMac.update(secret, SC_BLOCK_SIZE, (short) (SC_BLOCK_SIZE - ISO7816.OFFSET_CDATA)); scMac.update(secret, SC_BLOCK_SIZE, (short) (SC_BLOCK_SIZE - ISO7816.OFFSET_CDATA));
return scMac.verify(apduBuffer, (short) (ISO7816.OFFSET_CDATA + SC_BLOCK_SIZE), (short) (apduLen - SC_BLOCK_SIZE), apduBuffer, ISO7816.OFFSET_CDATA, SC_BLOCK_SIZE); return scMac.verify(apduBuffer, (short) (ISO7816.OFFSET_CDATA + SC_BLOCK_SIZE), (short) (apduLen - SC_BLOCK_SIZE), apduBuffer, ISO7816.OFFSET_CDATA, SC_BLOCK_SIZE);
} }
}
/** /**
* Sends the response to the command. This the given SW is appended to the data automatically. The response data must * Sends the response to the command. This the given SW is appended to the data automatically. The response data must
@ -296,10 +313,18 @@ public class SecureChannel {
} }
public void computeAESMAC(short len, byte[] apduBuffer) { public void computeAESMAC(short len, byte[] apduBuffer) {
if (scMac == null) {
scMacCipher.init(scMacKey, Cipher.MODE_ENCRYPT);
short encLen = scMacCipher.update(apduBuffer, (short) 0, (short) 1, macCipherBuf, (short) 0);
encLen += scMacCipher.update(secret, SC_BLOCK_SIZE, (short) (SC_BLOCK_SIZE - 1), macCipherBuf, encLen);
encLen += scMacCipher.doFinal(apduBuffer, (short) (ISO7816.OFFSET_CDATA + SC_BLOCK_SIZE), len, macCipherBuf, encLen);
Util.arrayCopyNonAtomic(macCipherBuf, (short)(encLen - SC_BLOCK_SIZE), apduBuffer, ISO7816.OFFSET_CDATA, SC_BLOCK_SIZE);
} else {
scMac.init(scMacKey, Signature.MODE_SIGN); scMac.init(scMacKey, Signature.MODE_SIGN);
scMac.update(apduBuffer, (short) 0, (short) 1); scMac.update(apduBuffer, (short) 0, (short) 1);
scMac.update(secret, SC_BLOCK_SIZE, (short)(SC_BLOCK_SIZE - 1)); scMac.update(secret, SC_BLOCK_SIZE, (short) (SC_BLOCK_SIZE - 1));
scMac.sign(apduBuffer, (short)(ISO7816.OFFSET_CDATA + SC_BLOCK_SIZE), len, apduBuffer, ISO7816.OFFSET_CDATA); scMac.sign(apduBuffer, (short) (ISO7816.OFFSET_CDATA + SC_BLOCK_SIZE), len, apduBuffer, ISO7816.OFFSET_CDATA);
}
} }
/** /**