Patent ID: 7146006
Filing Date: 2006-12-05
Classification: G06F,G06K,G06Q,G07F,H04L

Abstract:
1. A method for performing cryptographic operations using keys obtained from random numbers that are generated using the Data Encryption Standard (DES) algorithm with a secret key K, said method taking as input a random integer s of size 64 bits, and an integer m, said method sending back as output m 64-bit random integers x 1 , x 2 , . . . , x m , said method comprising the following steps: a) with the DES algorithm and using the key K, encrypting a value D representing date data and putting the result in an integer variable I; b) for j in the range 1 to m: b1) replacing s by s XOR I, b2) defining an integer variable y equal to the result of the encryption of s with the DES algorithm using the key K, b3) putting in x b4) replacing s with y XOR I, b5) putting in s the result of the encryption of s with the DES algorithm using the secret key K; c) returning as output the succession (x d) obtaining keys corresponding to said values x e) performing cryptographic operations with said keys.