Patent ID: 6918035

Claim:
A method for authenticating a first party at a second party, comprising: (a) receiving a random number from said first party as a first challenge; (b) incrementing a count value in response to receiving said first challenge; (c) generating a first challenge response by performing a keyed cryptographic function (KCF) on said first challenge and said count value using a first key; (d) transferring said count value, as a second challenge, and said first challenge response to said first party; (e) receiving a second challenge response from said first party, said second challenge response being a result of performing said KCF on said second challenge using said first key; and (f) verifying said first party based on said second challenge and said second challenge response, wherein said first party is a network of a wireless system and said second party is a mobile, and said step (c) generates said first challenge response by performing said KCF on said first challenge, said count value and type data using said first key, said type data indicating a type of protocol being performed by said network and said mobile.