Patent ID: 6459791
Filing Date: 2002-10-01
Classification: G06F,H04L

Abstract:
A public-key cryptography method based on the discrete logarithm using the calculation of the quantity gkmodp where p is a prime number referred to as the modulus, k a random number normally of length n bits and g an integer referred to as the base, in which an entity E performs authentication and/or signature and/or encoding operations, comprising exchanges of signals with another entity in which this quantity acts, characterised in that it includes the following steps for the entity:generating a random exponent k of length N bits, N being equal to n+b bits, calculating the Hamming weighting C of this exponent and comparing it with a value h fixed in advance, checking whether the random value k fulfils the condition C&gE;h rejecting the random value k where the Hamming weighting is less than h and recommencing the generation of new exponents until an exponent satisfying this condition is obtained, or keeping this value in the contrary case, calculating the expression gkmodp from the kept value, using this expression in the exchanges of electronic signals with the other entity.