Patent ID: 8645703
Filing Date: 2014-02-04
Classification: H04L

Abstract:
1. A method of encrypting a message in a manner that counters power analysis attacks, wherein a long-term private cryptographic key has been selected and a long-term public cryptographic key has been determined based on the long-term private cryptographic key and a base point on a given elliptic curve, the base point having a prime order, the method comprising: determining a modular inverse of the long-term private cryptographic key; generating a sessional private cryptographic key and a sessional public cryptographic key; determining an implicit signature based on the modular inverse of the long-term private cryptographic key, the sessional private cryptographic key, the sessional public cryptographic key and the long-term private cryptographic key; determining a shared secret cryptographic key based on the implicit signature; and encrypting a message using the shared secret cryptographic key; wherein determining the implicit signature comprises evaluating: wherein S k d d u is the order of the base point.