Why does HMAC_SHA256 not supported?

[Joevictor]

The code given below is from my applet which implements HMAC_SHA256. In my applet, I have to sign recData byte array using encryData byte array.

Code: Select all

 Signature m_sessionMAC = null;
    HMACKey keyType = null;
    Sign = new byte[64];

    bytesRead = apdu.setIncomingAndReceive();

    m_sessionMAC = Signature.getInstance(Signature.ALG_HMAC_SHA_256, false);

    keyType = (HMACKey) KeyBuilder.buildKey(KeyBuilder.TYPE_HMAC, KeyBuilder.LENGTH_HMAC_SHA_256_BLOCK_64, false); 
    keyType.setKey(encryData,(short) 0, (short) encryData.length);
    m_sessionMAC.init(keyType, Signature.MODE_SIGN);

    echoOffset = m_sessionMAC.sign(recData, ISO7816.OFFSET_CDATA, ISO7816.OFFSET_LC, Sign , (short)0); 
    Util.arrayCopyNonAtomic(Sign, ( short ) 0, recData, ( short ) 0, echoOffset); 
    apdu.setOutgoingAndSend( ( short ) 0, (short) echoOffset );

For my applet, I always got 6A81(Function not supported). And I can not understand this well. Why does HMAC_SHA256 not supported? Hope someone help me out.

[UNKNwYSHSA]

You can debug step by step, which line the exception raised.