Patent ID: 7779259

Claim:
A method of transporting a session key K from a first correspondent A to a second correspondent B in a public key communication system to permit exchange of information therebetween over a communication channel, said first correspondent A having stored in its memory a private key a and a corresponding public key p A derived from a generator α and said private key a, and said second correspondent B having stored in its memory a private key b and a corresponding public key p B derived from said generator α and said private key b, said method comprising the steps of: (a) said first correspondent A obtaining a random integer x and computing a value r A from said generator α and said random integer x; (b) said first correspondent A computing a signature S A from said random integer x, said value r A , and said private key a to bind said random integer x and said private key a; (c) said first correspondent A computing said session key K from said random integer x and public information pertaining to said second correspondent B; (d) said first correspondent A forwarding to said second correspondent B a message including said value r A and said signature S A ; (e) said second correspondent B verifying that a second value computed using said generator α, said signature S A , said value r A , and public information pertaining to said first correspondent A is equal to said value r A received from said first correspondent A; and (f) said second correspondent B computing said session key K from said value r A , and from information private to said second correspondent B, said information private to said second correspondent B being related to said public information pertaining to said second correspondent B.