Patent ID: 7222362

Claim:
A method for accepting from a user an assertion of at least one anonymous credential (AC) granted to a party having a master secret; said master secret comprising a private key, s, of a public/private key encryption pair and said public key, EU, generated by a commitment algorithm, C, performed on private key, s, and denoted C(s), said assertion repeated at least once, said method comprising the steps: receiving said assertion from said user; for said received assertion and each repeated instance, thereof: receiving from said user an initiation of a multi-party protocol in which a prover provides a proof of knowledge of said master secret; verifying said proof; wherein said proof is a zero knowledge proof of knowledge; accepting said at least one AC only if said verifying step is successful, wherein requiring successful completion of said proof for said received assertion and each repeated instance, thereof before accepting said at least one AC prevents transferring said at least one AC without also transferring said master secret, and said at least one AC granted by an organization O i based on receiving a request for each of said at least one AC, (O i ::x i ) from a party, authenticating an identity of said party, generating a message, m i =<C(s), (O i ::x i )>, generating a signed message σ i =S oi (m i ) wherein S oi is a public signing key of said O i , and sending σ i to said party.