Patent ID: 6965673

Claim:
A method for determining secret information contained in a first cryptography device using a second cryptography device, the method comprising the steps of: a. generating an electrical signal comprising a stream of bits containing a correct digital signature in said first cryptography device; b. transmitting the electrical signal containing the correct digital signature to said second cryptography device; c. placing said first cryptography device under physical stress and in response to the physical stress, generating an electrical signal comprising a stream of bits containing an incorrect digital signature in said first cryptography device; d. transmitting the electrical signal containing the incorrect digital signature to said second cryptography device; e. in a processor in said second cryptographic device, determining secret information q stored in said first cryptography device using: gcd ( E−Ê,N )= q wherein N is a product of prime numbers, and one of the prime numbers is q; and f. generating an output electrical signal comprising a stream of bits containing the secret information used to generate the correct signature.