Analysis and Enhancement of Ring Oscillators Based Physical Unclonable Functions in FPGAs

The paper analyzes and proposes some enhancements of Ring Oscillator based Physical Unclonable Functions (PUFs) that are used to extract a unique signature of an integrated circuit in order to be used for device authentication purposes and/or key generation. We analyze in more details the concept developed by Suh et al. in 2007. Contrary to what authors claim, we show that the designer of the Ring Oscillator PUFs implemented in FPGAs needs precise control of placement and routing in order to get unique responses and repeatable results for each individual device, especially when the rest of the reconfigurable device should remain up gradable. One main disadvantage of the original design is its high power consumption. We propose a simple improvement that reduces the consumption of the PUF published by Suh et al. by up to 96.6\%. Last but not least, we point out that ring oscillators significantly influence one another and can even be locked. This questions the reliability of the PUF and should be taken into account during the design.

[1]  G. Edward Suh,et al.  Physical Unclonable Functions for Device Authentication and Secret Key Generation , 2007, 2007 44th ACM/IEEE Design Automation Conference.

[2]  Vincent Rijmen,et al.  The WHIRLPOOL Hashing Function , 2003 .

[3]  Sergei Skorobogatov,et al.  Semi-invasive attacks: a new approach to hardware security analysis , 2005 .

[4]  Srinivas Devadas,et al.  Silicon physical random functions , 2002, CCS '02.

[5]  Jorge Guajardo,et al.  FPGA Intrinsic PUFs and Their Use for IP Protection , 2007, CHES.

[6]  Saar Drimer,et al.  Volatile FPGA design security { a survey , 2008 .

[7]  G. Edward Suh,et al.  Extracting secret keys from integrated circuits , 2005, IEEE Transactions on Very Large Scale Integration (VLSI) Systems.

[8]  Jorge Guajardo,et al.  Extended abstract: The butterfly PUF protecting IP on every FPGA , 2008, 2008 IEEE International Workshop on Hardware-Oriented Security and Trust.

[9]  Stephen A. Benton,et al.  Physical one-way functions , 2001 .

[10]  Markus G. Kuhn,et al.  Tamper resistance: a cautionary note , 1996 .

[11]  R. Pappu,et al.  Physical One-Way Functions , 2002, Science.

[12]  Markus G. Kuhn,et al.  Low Cost Attacks on Tamper Resistant Devices , 1997, Security Protocols Workshop.

[13]  Nathalie Bochard,et al.  Enhancing security of ring oscillator-based trng implemented in FPGA , 2008, 2008 International Conference on Field Programmable Logic and Applications.

[14]  Peter Y. K. Cheung,et al.  Within-die delay variability in 90nm FPGAs and beyond , 2006, 2006 IEEE International Conference on Field Programmable Technology.