Patent ID: 6944778

Claim:
A method for testing an integrated circuit containing hardware and/or software parts having a confidential nature, using a tester, wherein this method comprises the steps of: in said integrated circuit: generating a random number by a generator, ciphering this random number using a key stored in said integrated circuit via a ciphering algorithm to obtain a first password placed in a password register, and sending the random number to said tester, and, in said tester: ciphering in parallel said random number received using a key identical to that used in said integrated circuit via an identical ciphering algorithm to that implemented in said integrated circuit, to generate a second password, and sending said second password from the tester to said integrated circuit, then, in said integrated circuit, comparing said first and second passwords by comparing means, freeing a test path leading from said tester to said parts of a confidential nature by opening a barrier in the integrated circuit, only if the comparison establishes a match between said first and second passwords, and effecting the test of said elements of a confidential nature.