Patent ID: 7599491

Claim:
A computer-implemented method of masking a cryptographic operation comprising generation of a signature r, s in a public key elliptic curve cryptographic system, said operation utilizing both a long term private key d and a short term private key k, wherein r=Kx mod n with K being a public key derived from the short term private key k and a generating point G, Kx being the representation of the x coordinate of the key K and n the order of the generating point G, and wherein s=1/k (e+dr) with e being a hash of the message to be signed and d being the long term private key, said method comprising the steps of: applying masking values to each of said long term private key and short term private key during at least a portion of said cryptographic operation to produce a result, said result corresponding to that obtained without application of said masking values whereby observation of said private keys is inhibited by said masking values during said cryptographic operation.