Physically Unclonable Functions (PUF) are a unique and stable physical characteristics of a piece of hardware, which emerge due to variations in the fabrication processes. PUF can be considered a type of fingerprint that is unique to each device. PUFs are a promising cryptographic primitive, which can enable secure key storage, hardware-based device identification, or even serve as basis for more advance cryptographic protocols. Most PUF constructions presented by other researchers have required an addition of new hardware or special FPGA implementations for their operation. This talk will present our research on new, run-time accessible PUFs based on DRAM memories. The presented work leverages decay characteristics intrinsic to DRAM in commodity, off-the-shelf systems. The DRAM decay-based PUFs requires no additional hardware or use of special FPGA-based setup. One of the key advantages of the new PUF construction is that it can be queried during run-time of a Linux system. Furthermore, by exploiting different decay times of individual DRAM cells, the challenge-response space is increased. The new decay-based DRAM PUFs can be used in lightweight protocols for device authentication and secure channel establishment that will be presented in the talk as well. In addition, recent ideas about DRAM PUFs based on the Rowhammer effect will be discussed. The talk will conclude with some thoughts on current research challenges and opportunities regarding PUFs.
Jakub Szefer’s research interests are at the intersection of computer architecture, system software and hardware security. His research focuses on secure hardware-software architectures for servers and mobile devices, virtualization and cloud security, hardware security verification, physically unclonable functions, and hardware FPGA implementation of cryptographic algorithms. His research is supported through National Science Foundation and industry donations. He joined Yale University in summer 2013 as an Assistant Professor of Electrical Engineering, where he started the Computer Architecture and Security Laboratory (CAS Lab). Prior to joining Yale, he received Ph.D. and M.A. degrees in Electrical Engineering from Princeton University and worked with Prof. Ruby B. Lee on secure hardware architectures. He received B.S. with highest honors in Electrical and Computer Engineering from University of Illinois at Urbana-Champaign.