RESPONSE VALIDATION MECHANISM FOR TRIGGERING NON-INVASIVE RE-TEST ACCESS OF INTEGRATED CIRCUITS
In an embodiment of the invention, response validation offers increased integrated circuit security by using a unique password or re-test key for every integrated circuit manufactured. Non-invasive re-test of an IC can be performed using an encryption input.
1 . A method for triggering non-invasive re-test access of an integrated circuit comprising:
providing an encryption key to a first input of an encryption algorithm;
providing a device specific encryption value to a second input of the encryption algorithm;
wherein the encryption algorithm provides a stored response, the stored response determined by the encryption key and the device specific encryption value;
electronically storing the stored response in a non-volatile memory (NVM) on the integrated circuit;
electronically storing the device specific encryption value in the NVM on the integrated circuit;
providing the encryption key to the first input of the encryption algorithm;
reading the device read encryption input from the NVM into the second input of the encryption algorithm;
providing a validate response to the integrated circuit when the encryption algorithm verifies that the read encryption key and the device read encryption input are valid; and
retesting the integrated circuit.
2 . The method of claim 1 wherein the device specific encryption value is generated external to the integrated circuit.
3 . The method of claim 1 wherein the device specific encryption value is generated on the integrated circuit.