Cherry-Picking Reliable PUF Bits with Differential Sequence Coding

Matthias Hiller, Meng Day Mandel Yu, Georg Sigl

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

Silicon physical unclonable functions (PUFs) produce a sequence of response bits from chip-unique manufacturing variations. Since the response bits are physically derived, there is noise present. To generate bit-exact cryptographic keys, error correction algorithms are used. The error correction is typically split into small processing blocks to reduce implementation complexity. The reliability of PUF responses varies from bit to bit, but there has been very little work so far that mathematically analyzes the effect of the block size on the reliability of PUF response sequences. We use the information theoretical concept of typicality to show that the probability of drawing an unreliable sequence decreases exponentially with the block size. We present differential sequence coding that scales efficiently across larger block sizes without having the super-linear increase in decoding complexity of prior approaches. It scans the entire PUF response sequentially and then only operates on one single, maximally reliable, block to generate the cryptographic key. Our sample FPGA implementation with a convolutional code is designed for a popular SRAM PUF scenario. It generates a 128-bit key for an average input bit error probability of 15% with an output bit error probability of 6.14· 10-9 and only uses 974 PUF bits and 1, 108 helper data bits. There are 36% less PUF bits and 71% less helper data bits than the best previous individual results in both criteria without increasing the implementation size of the key generation module noticeably.

Original languageEnglish
Article number7480444
Pages (from-to)2065-2076
Number of pages12
JournalIEEE Transactions on Information Forensics and Security
Volume11
Issue number9
DOIs
StatePublished - Sep 2016

Keywords

  • FPGA
  • Physical unclonable function (Puf)
  • convolutional code
  • differential sequence coding (Dsc)
  • error correction
  • syndrome coding
  • typicality

Fingerprint

Dive into the research topics of 'Cherry-Picking Reliable PUF Bits with Differential Sequence Coding'. Together they form a unique fingerprint.

Cite this