Improving the Robustness of Ring Oscillator TRNGs

A ring oscillator based true-random number generator design (Rings design) was introduced in [1]. The design was rigorously analyzed under a mathematical model and its performance characteristics were established. In this paper we focus on the practical aspects of the Rings design on a reconfigurable logic platform and determine their implications on the earlier analysis framework. We make recommendations for avoiding pitfalls in real-life implementations by considering ring interaction, transistor level effects, narrow signal rejection, transmission line attenuation, and sampler bias. Furthermore, we present experimental results showing that changing operating conditions such as the power supply voltage or the operating temperature may affect the output quality when the signal is subsampled. Hence, an attacker may shift the operating point via a simple non-invasive influence and easily bias the TRNG output. Finally, we propose modifications to the design which significantly improves ...

• Type: Journal
• Year: 2010
• Where: TRETS
• Authors: Sang-Kyung Yoo, Deniz Karakoyunlu, Berk Birand, Berk Sunar
• Keywords: Design, Hardware, Narrow Signal Rejection, Number Generator Design, TRETS 2010