Patent ID: 7603560

Claim:
A computer-implemented method for authenticating a digital signature comprising: receiving ciphertext and a digital signature (u, P) associated with the ciphertext on a receiver device, where u is an integer, P is a point on an elliptic curve having an x-coordinate X1, and the ciphertext is an encrypted message; computing a point Q=u°(X1/1) on the elliptic curve; computing a point R=P+M(ciphertext, P)° ourPub on the elliptic curve, where ourPub is a public key and M is a message digesting function or a hashing function; and determining that the digital signature is valid if the elliptic curve points Q and R have identical x-coordinates and that the digital signature is invalid if the elliptic curve points Q and R do not have identical x-coordinates, wherein the determining is performed by a processor of the receiver device.