From bca030f0695c92294c5c2de993a6062a999a5ecc Mon Sep 17 00:00:00 2001
From: Michele Balistreri <michele@bitgamma.com>
Date: Mon, 23 Dec 2019 17:33:49 +0100
Subject: [PATCH] reduce NVM writes

---
 .../java/im/status/keycard/KeycardApplet.java     |  1 -
 .../java/im/status/keycard/SecureChannel.java     | 15 ---------------
 2 files changed, 16 deletions(-)

diff --git a/src/main/java/im/status/keycard/KeycardApplet.java b/src/main/java/im/status/keycard/KeycardApplet.java
index 89303a2..f89aee7 100644
--- a/src/main/java/im/status/keycard/KeycardApplet.java
+++ b/src/main/java/im/status/keycard/KeycardApplet.java
@@ -374,7 +374,6 @@ public class KeycardApplet extends Applet {
     pin.reset();
     puk.reset();
     secureChannel.reset();
-    secureChannel.updateSecureChannelCounter();
 
     byte[] apduBuffer = apdu.getBuffer();
 
diff --git a/src/main/java/im/status/keycard/SecureChannel.java b/src/main/java/im/status/keycard/SecureChannel.java
index b278ce3..b70751b 100644
--- a/src/main/java/im/status/keycard/SecureChannel.java
+++ b/src/main/java/im/status/keycard/SecureChannel.java
@@ -13,7 +13,6 @@ public class SecureChannel {
   public static final short PAIRING_KEY_LENGTH = SC_SECRET_LENGTH + 1;
   public static final short SC_BLOCK_SIZE = Crypto.AES_BLOCK_SIZE;
   public static final short SC_OUT_OFFSET = ISO7816.OFFSET_CDATA + (SC_BLOCK_SIZE * 2);
-  public static final short SC_COUNTER_MAX = 100;
 
   public static final byte INS_OPEN_SECURE_CHANNEL = 0x10;
   public static final byte INS_MUTUALLY_AUTHENTICATE = 0x11;
@@ -33,8 +32,6 @@ public class SecureChannel {
   private byte[] secret;
   private byte[] pairingSecret;
 
-  private short scCounter;
-
   /*
    * To avoid overhead, the pairing keys are stored in a plain byte array as sequences of 33-bytes elements. The first
    * byte is 0 if the slot is free and 1 if used. The following 32 bytes are the actual key data.
@@ -391,18 +388,6 @@ public class SecureChannel {
     return remainingSlots;
   }
 
-  /**
-   * Called before sending the public key to the client, gives a chance to change keys if needed.
-   */
-  public void updateSecureChannelCounter() {
-    if (scCounter < SC_COUNTER_MAX) {
-      scCounter++;
-    } else {
-      scKeypair.genKeyPair();
-      scCounter = 0;
-    }
-  }
-
   /**
    * Resets the Secure Channel, invalidating the current session. If no session is opened, this does nothing.
    */