Patent ID: 7260723

Claim:
A method for verifying a signature for a message m in a data communication system established between a sender and a verifier, said sender having generated in a secure computer system a masked signature having a first signature component r computed using a first short term public key derived from a first short term private key; a second signature component s computed using a second short term private key on said message m, a long term private key, and said first signature component r; and a third signature component c computed using said first and second short term private keys, said method for verifying comprising said verifier: a) obtaining a regular signature derived from said masked signature (r, s, c), said regular signature having said first signature component r, and another signature component s computed using said second signature component s and said third signature component c; b) recovering a point on an elliptic curve defined over a finite field using said message m and said another signature component s ; c) converting an element of said point to an integer; d) calculating a value r′ using said integer; and e) verifying said regular signature (r, s ) if said value r′ is equal to said first signature component r.