On the Effectiveness of the Remanence Decay Side-Channel to Clone Memory-Based PUFs

We present a side-channel attack based on remanence decay in volatile memory and show how it can be exploited effectively to launch a non-invasive cloning attack against SRAM PUFs — an important class of PUFs typically proposed as lightweight security primitive with low overhead by using the existing memory of the underlying device. We validate our approach against two SRAM PUF implementations in 65 nm CMOS ASICs. We discuss countermeasures against our attack and propose the constructive use of remanence decay to improve the cloning-resistance of SRAM PUFs. Moreover, as a further contribution of independent interest, we show how to use our evaluation results to significantly improve the performance of the recently proposed TARDIS scheme, which is based on remanence decay in SRAM and used as a time-keeping mechanism for low-power clock-less devices.