Patent ID: 7020281
Filing Date: 2006-03-28
Classification: G06F,H04L

Abstract:
1. A method of generating a result of a group operation, said method performed by a computing apparatus an integral number of times on a selected element of a group, said group having a plurality of elements including a group identity element, said method comprising the steps of: a) representing said integral number as a binary vector of bits having one value or another, b) initialising said result to that of said group identity element; c) selecting in sequence a predetermined number of successive bits of said vector and for each of said selected bits; i) performing said group operation on said result to derive a first intermediate value, ii) obtaining a second intermediate value by performing said group operation on said first intermediate value and said selected element when said computing apparatus is in one state and by performing said group operation on said intermediate value and an inverse of said selected element when said computing apparatus is in another state; iii) replacing said result with said second intermediate value, iv) selecting a state of said computing apparatus by examining an immediately preceding bit and maintaining the current state when said bits are of the same value and changing to said other state when said bits are different; d) repeating step c) for said predetermined number of said bits and performing said group operation on any remaining bits of said vector, whereby each of said predetermined bits of said of said vector is processed with similar operations, thereby inhibiting disclosure of said sequence of predetermined bits to produce said result; and e) outputting said result for use in subsequent computations.