Eric Townsend extracted some of the text from RFC 1421 (PEM) and sent it to me. Thanks! In it are contained the patent numbers for PKP's patents, which I present below. Note: PKP has since acquired rights to the Schnorr patent; it relates to DSA. Eric ----------------------------------------------------------------------------- Cryptographic Apparatus and Method ("Diffie-Hellman")............................... No. 4,200,770 Public Key Cryptographic Apparatus and Method ("Hellman-Merkle").................... No. 4,218,582 Cryptographic Communications System and Method ("RSA")................................... No. 4,405,829 Exponential Cryptographic Apparatus and Method ("Hellman-Pohlig").................... No. 4,424,414