SLED: Sequential Logic Encryption Using Dynamic Keys
Yasaswy Kasarabada, Vaishali Muralidharan, Ranga R. Vemuri · 2020
Logic encryption has emerged as a prominent Design-for-Trust technique to prevent threats in VLSI supply chain such as overproduction and IP piracy. Traditional logic encryption methods have relied on using static one-time-programmable (OTP) keys for locking the design. Sequential obfuscation schemes have demonstrated the advantages of utilizing the dynamic nature of sequential circuits in increasing security. However, they still rely on a secure OTP memory with fixed key values to enforce encryption. In this paper, we propose a new sequential logic locking method that uses dynamic key values obtained from the secure memory to determine corruption on the payload signals. A novel technique to generate these dynamic keys from a traditional static memory is also presented. We obfuscate various sequential circuits to evaluate the effectiveness of this scheme against oracle-based attacks.