Feedforward Xored Secure Scan Structure for Crypto Chips

Scan structure increase the testability of crypto chips,however,it might be misused as a path of side-channel attack to leak out the secret information of crypto chips.To cope with such a challenge,a feedforward xored secure scan structure is proposed.The scan structure conducts an input/output linear transformation on the test patterns to hardware encrypt the test patterns by introducing feedforward xored secure scan flip-flops in the structure;and then the security of the structure is analyzed and its test pattern generation algorithm is presented.Experimental results show that the structure can be used as an effective countermeasure against scan-based side-channel attack and reset attack,while high test coverage of the traditional scan structure is maintained.