Patent ID: 6975729

Claim:
A method for facilitating a key exchange that operates with a pre-shared secret key and that hides identities of parties involved in the key exchange, comprising: initially establishing a negotiated secret key between a first party and a second party by performing communications between the first party and the second party across a network; wherein the communications between the first party and the second party do not allow an eavesdropper to determine the negotiated secret key; encrypting an identifier for the first party using a first key that is a function of a group secret key and the negotiated secret key to form an encrypted identifier; wherein the group secret key is known to members of a group, including the first party and the second party, but is kept secret from parties outside of the group; sending the encrypted identifier from the first party across the network to the second party; allowing the second party to decrypt the encrypted identifier by using the group secret key and the negotiated secret key; allowing the second party to use the identifier to look up the pre-shared secret key in a table of pre-shared secret keys that was previously established between the first party and the second party; and using the pre-shared secret key in forming at least one subsequent communication between the first party and the second party.