Low Cost Built in Self Test for Public Key Crypto Cores
Duko Karaklajic, Miroslav Kneevic, Ingrid M.R. Verbauwhede · 2010
The testability of cryptographic cores brings an extra dimension to the process of digital circuits testing security. The benefits of the classical methods such as the scan-chain method introduce new vulnerabilities concerning the data protection. The Built-In Self-Test (BIST) is considered to be the most suitable countermeasure for this purpose. In this work we propose the use of a digit-serial multiplier over GF (2m), that is at the heart of many public-key cryptosystems, as a basic building block for the BIST circuitry. We show how the multiplier can be configuredto operate as a Test Pattern Generator and a Signature Analyzer. Furthermore, the multiplier becomes a fully self-testable design. All the additional features come at the cost of only a few extra gates. With a hardware overhead of 0.33 % this approach makes the multiplier perfectly suitable for low-end embedded devices.