/**
* Processes the first <code>len</code> bytes in <code>input</code>, starting at <code>offset
* </code>.
*
* @param input the input buffer.
* @param offset the offset in <code>input</code> where the input starts.
* @param len the number of bytes to process.
*/
protected void engineUpdate(byte input[], int offset, int len) {
hmac.update(input, offset, len);
}
protected void engineUpdate(ByteBuffer input) {
hmac.update(input);
}
/**
* Processes the given byte.
*
* @param input the input byte to be processed.
*/
protected void engineUpdate(byte input) {
hmac.update(input);
}
/**
* Initializes the HMAC with the given secret key and algorithm parameters.
*
* @param key the secret key.
* @param params the algorithm parameters.
* @exception InvalidKeyException if the given key is inappropriate for initializing this MAC.
* @exception InvalidAlgorithmParameterException if the given algorithm parameters are
* inappropriate for this MAC.
*/
protected void engineInit(Key key, AlgorithmParameterSpec params)
throws InvalidKeyException, InvalidAlgorithmParameterException {
hmac.init(key, params);
}
/**
* Returns the length of the HMAC in bytes.
*
* @return the HMAC length in bytes.
*/
protected int engineGetMacLength() {
return hmac.getDigestLength();
}
/**
* Resets the HMAC for further use, maintaining the secret key that the HMAC was initialized with.
*/
protected void engineReset() {
hmac.reset();
}
/**
* Completes the HMAC computation and resets the HMAC for further use, maintaining the secret key
* that the HMAC was initialized with.
*
* @return the HMAC result.
*/
protected byte[] engineDoFinal() {
return hmac.doFinal();
}