generateHMAC(byte[], short)->generateHMAC()

src/main/java/com/josh/vku2f/CTAP2.java

@@ -445,7 +445,7 @@ public class CTAP2 extends Applet implements ExtendedLength {
 		cborEncoder.encodeByteString(idSecret.encryptedCx, (short) 0, (short) idSecret.encryptedCx.length);
 
 		// generate HMAC
-		idSecret.generateHMAC(scratch, (short) 0);
+		idSecret.generateHMAC();
 
 		apdu.setOutgoing();
 		apdu.setOutgoingLength(cborEncoder.getCurrentOffset());

src/main/java/com/josh/vku2f/IDSecret.java

@@ -88,7 +88,7 @@ public class IDSecret {
 	/**
 	 *  AES(aesRawKey, SHA256(IDx||Cx))
 	 */
-	public void generateHMAC(byte[] outputBuffer, short outputOffset){
+	public void generateHMAC(){
 		Util.arrayCopy(IDx.str, (short)0, scratch, (short)0, (short)IDx.str.length);
 		Util.arrayCopy(Cx, (short)0, scratch, (short)IDx.str.length, (short)Cx.length);
 		short scratchLength = (short)(IDx.str.length + Cx.length);
@@ -101,17 +101,15 @@ public class IDSecret {
 		sha256.doFinal(scratch, updateOffset, scratchLength, scratch, (short)0);
 		// pkcs#7 padding
 		Util.arrayFill(scratch, (short)32, (short)16, (byte)0x10);
-		aesEncrypt.update(scratch, (short)0, (short)16, outputBuffer, outputOffset);
-		aesEncrypt.update(scratch, (short)16, (short)16 , outputBuffer, (short)(outputOffset+16) );
-		aesEncrypt.doFinal(scratch, (short)32, (short)16, outputBuffer, (short)(outputOffset+32) );
-
-		Util.arrayCopy(outputBuffer, (short)0, hmac, (short)0, (short)hmac.length );
+		aesEncrypt.update(scratch, (short)0, (short)16, hmac, (short)0);
+		aesEncrypt.update(scratch, (short)16, (short)16 , hmac, (short)16 );
+		aesEncrypt.doFinal(scratch, (short)32, (short)16, hmac, (short)32 );
 	}
 
 	public void next(){
 		plusOne(Cx);
 		encryptCx();
-		generateHMAC(tempBuffer, (short)0);
+		generateHMAC();
 	}
 
 	/**