D-PUF: An Intrinsically Reconfigurable DRAM PUF for Device Authentication and Random Number Generation

Physically Unclonable Functions (PUFs) have proved to be an effective and low-cost measure against counterfeiting by providing device authentication and secure key storage services. Memory-based PUF implementations are an attractive option due to the ubiquitous nature of memory in electronic devices and the requirement of minimal (or no) additional circuitry. Dynamic Random Access Memory-- (DRAM) based PUFs are particularly advantageous due to their large address space and multiple controllable parameters during response generation. However, prior works on DRAM PUFs use a static response-generation mechanism making them vulnerable to security attacks. Further, they result in slow device authentication, are not applicable to commercial off-the-shelf devices, or require DRAM power cycling prior to authentication. In this article, we propose D-PUF, an intrinsically reconfigurable DRAM PUF based on the idea of DRAM refresh pausing. A key feature of the proposed DRAM PUF is reconfigurability, that is, by varying the DRAM refresh-pause interval, the challenge-response behavior of the PUF can be altered, making it robust to various attacks. The article is broadly divided into two parts. In the first part, we demonstrate the use of D-PUF in performing device authentication through a secure, low-overhead methodology. In the second part, we show the generation of true random numbers using D-PUF. The design is implemented and validated using an Altera Stratix IV GX FPGA-based Terasic TR4-230 development board and several off-the-shelf 1GB DDR3 DRAM modules. Our experimental results demonstrate a 4.3×-6.4× reduction in authentication time compared to prior work. Using controlled temperature and accelerated aging tests, we also demonstrate the robustness of our authentication mechanism to temperature variations and aging effects. Finally, the ability of the design to generate random numbers is verified using the NIST Statistical Test Suite.