code: public boolean isValidMac(String hmac) throws HawkException {
  		String this_hmac = this.generateHmac();
  		return Util.fixedTimeEqual(this_hmac, hmac);
  	}
docs: Check whether a given HMAC value matches the HMAC for this HawkContext.
  
  @param hmac
  The HMAC value to test.
  @return true if the HMAC matches the HMAC computed for this context,
  false otherwise.
  @throws HawkException