RSAREF version 1.1 (and higher) has Diffie Helman key exchange in it. I suggest you ftp this from rsa.com and try it. -derek Derek Atkins, SB '93 MIT EE, G MIT Media Laboratory Secretary, MIT Student Information Processing Board (SIPB) PGP key available from pgp-public-keys@pgp.mit.edu warlord@MIT.EDU PP-ASEL N1NWH