Générateurs de nombres véritablement aléatoires à base d'anneaux asynchrones : conception, caractérisation et sécurisation

摘要

True Random Number Generators (TRNG) are ubiquitous in many critical cryptographic applications (key generation, DSA signatures, etc). While many TRNG designs exist in literature, only a few of them deal with security aspects, which is surprising considering that they are low-level primitives in a cryptographic system (a weak TRNG can jeopardize a whole cryptographic system). The objective of this thesis was to study the advantages of asynchronous design techniques in order to build true random number generators that are secure and robust. We especially focused on digital oscillators called self-timed rings (STR), which use a handshake request and acknowledgement protocol to organize the propagation of data. Using some of the unique properties of STRs, we propose a new TRNG principle, with a detailed theoretical study of its behavior, and an evaluation of the TRNG core in ASICs and FPGAs. We demonstrate that this new principle allows to generate high quality random bit sequences with a very high throughput (> 100 Mbit/s). Moreover, it enables a realistic estimation for the entropy per output bit (this entropy level can be tuned using the entropy extractor parameters). We also present a complete methodology to design the TRNG, to properly set up the architecture with regards to the level of noise in the circuit, and to secure it against attacks and failures