A sequence dependent challenge-response PUF using 28nm SRAM 6T bit cell

Conventionally, SRAM PUFs are only used for chip ID. The proposed sequence dependent PUF expands the challenge-response space of an SRAM PUF by an order of rows
^{(sequence length-1)}
, making it suitable for authentication. In addition, it has a sequence dependent non-linear behavior making it more immune to machine learning attacks. In 28nm, the 64×64 SRAM-based PUF has a bit area of 388F
²
with energy ranging from 30fJ/bit–88fJ/bit at 0.6V. It also provides high throughput, from 2.2Gbps to 6.8Gbps at 0.9V.