On the Use of Scan Chain to Improve Physical Attacks (Extended Abstract)

An unprotected scan-chain makes a perfect back-door in a secure chip. Therefore, many secure chips disable the access to the scan-chains once the testing is completed. In this paper, we consider an attack that is carried out on a blank chip. The scan-chain is still accessible, yet there is no key to be attacked. We show that the attacker can use the scan chain to reveal information that can be used to improve other physical attacks, such side-channel analysis, fault analysis and probing analysis.