Patent ID: 7788479
Filing Date: 2010-08-31
Classification: H04L

Abstract:
1. A method of ensuring that only randomly-generated numbers that have passed a built-in self-test (BIST) are used to perform cryptographic functions comprising: generating a random number; performing a BIST on the generated random number in a random number generator core (RNG core); and transferring to a cryptographic device, using one transmission line, the generated random number when the generated random number passed the BIST, and transferring to the cryptographic device, using the one transmission line, a signal when the generated random number failed the BIST, the signal being a continuous transfer of a pre-determined number which indicates that the generated random number has failed the BIST, wherein the one transmission line is the only coupling between the RNG core and the cryptographic device capable of transmitting (i)the generated random number, and (ii)the signal, wherein the cryptographic device is configured to receive both the generated random number and the signal from the RNG core on the one transmission line, the generated random number being used for cryptographic functions by the cryptographic device.