Patent ID: 8402287
Filing Date: 2013-03-19
Classification: G06F,H04L

Abstract:
1. A cryptographic mechanism involving a secret D which can be represented as an n-bit number {d 0 , d 1 , . . . d n−1 } 2 , the cryptographic mechanism being arranged to calculate an output element OUT equal to X D , X being an element of a monoid {M, *}, the cryptographic mechanism comprising a first variable VAR 0 , a second variable VAR 1 , and computer program instructions to cause a processor of a cryptographic device to perform the steps of: a. generating a random element MSK_INPUT (R); b. creating a masked element MASKED_X (VAR c. calculating the masked output element MASKED_OUT (VAR d. calculating an output mask MSK_OUTPUT (MSK e. calculating the output element OUT using the masked output element MASKED_OUT and the output mask MSK_OUTPUT; and wherein the step d occurs at any time between step a and step e, and wherein the steps a, b, c and e are consecutive.