Design Of Truly Random Number Generator Based On Resistor Thermal Noise And Oscillator

With the development of electronics and communication technologies, information security becomes more and more important, and cryptography is the best and the only way to guarantee the security. In cryptographic applications, random numbers are needed whether for the generation of cryptographic keys or for the random initialization of certain variables in cryptographic protocols. To meet the ultimate requirement of security, completely unpredictable truly random numbers must be adopted, which have the intrinsical property of nonperiodicity other than pseudo random numbers.In this paper, the definition and applications of random number are introduced firstly. Then three main methods to carry out on-chip truly random number generator (TRNG) are analyzed: direct thermal noise amplification of a resistor, jittered oscillator sampling and discrete-time chaotic map. Among them, the last kind of TRNG is suspected by some cryptographists, since its generating mechanism is from mathematic chaotic maps. So the on-chip embeddable TRNG based on thermal noise and the one based on oscillator are designed in this paper.The proposed TRNG based on thermal noise includes optimized designs of low noise op-amp, comparator and offset compensation circuit, which can acquire better randomness comparing to traditional designs. And TRNG based on oscillator includes bandgap, triangular wave oscillator (including charge pump, OTA, two-stage op-amp and Schmitt trigger) and D flip-flop, and the whole design can guarantee getting higher periods'jitters. The above two TRNGs are both designed in HJTC 0.18μm CMOS mixed signal process, and the analog-part layouts have been finished.Finally, two kinds of designed TRNGs are tested through simulations respectively. And during this process, the time-domain thermal noise simulation method of a resistor and the measuring method of periods'jitters are developed. The simulation results show that both of the two proposed TRNGs can pass all of the randomness statistical tests at the same throughput of 10Mbit/s.