Statistical analysis and design of 6T SRAM cell for physical unclonable function with dual application modes

Abstract

Apart from performance and power efficiency, security is another critical concern in the modern memory sub-system design. SRAM, which is routinely used as a data preservation component, has now been developed into an effective primitive known as Physical Unclonable Function (PUF) for cryptographic key generation to protect the sensitive local information. Considering the constraints of hardware resource on the embedded systems, it is highly desirable to have an SRAM used both as a regular memory and a PUF to save the overheads of having these two functions implemented independently on different memory chips. Unfortunately, while process variations are the entropy sources for secure key generation, it impacts failure rates in memory accesses. This paper presents a statistical analysis on SRAM and provides an insight into how the SRAM cell geometry can be optimized to qualify it for both modes of operation simultaneously - a feasibility that has not been conceived before in the literature.