Patent ID: 7688975

Claim:
A method for exchanging dynamic encryption keys, comprising: (a) generating ( 102 ) a key exchange package ( 106 ) by an originator computer ( 14 ) that includes an electronic serial number (ESN) of a first token device ( 30 ) and a first challenge, wherein said first token device comprises an encryption processor and previously entered first shared secrets, and wherein said first token device can create an originator dynamic encryption key based on the first challenge from said originator computer and said first shared secrets; (b) transmitting ( 110 ) the key exchange package ( 106 ) to a recipient computer ( 14 A); (c) decomposing the key exchange package ( 106 ) to obtain key exchange information; (d) transmitting ( 112 ) the key exchange information to a server ( 16 A); wherein said server has a copy of said first shared secrets from said first token device and wherein said server additionally has a copy of second shared secrets that reside on a second token device attached to said recipient computer; (e) using said key exchange information and said first shared secrets on said server to reconstruct the originator dynamic encryption key ( 71 ) and also generating ( 116 ) a second challenge responsive to receipt of the key exchange information and using the second challenge and said second shared secrets to encrypt said originator dynamic encryption key ( 71 ) to produce an encrypted dynamic encryption key ( 71 E); (f) transmitting ( 118 ) the second challenge ( 128 ) and said encrypted dynamic encryption key ( 71 E) to the second token device coupled to the recipient computer; (g) using the second token device to decrypt the originator dynamic encryption key ( 71 ) based upon the second challenge, the second shared secrets, and the encrypted dynamic encryption key thus resulting in an exchange of dynamic encryption keys from said originator computer to said recipient computer.