In hopes of helping eliminate some of the more basic algorithm-specific interoperability problems, Pau-Chen Cheng and I have put together and submitted a HMAC Test Cases I-D that covers HMAC-MD5 and HMAC-SHA. I've put an advanced copy at: ftp://ftp.antd.nist.gov/pub/ipsec/draft-cheng-hmac-test-cases-00.txt. Rob G. rob.glenn@nist.gov