Chaos-Based RNG using Semiconductor Lasers with Parameters Variation Tolerance

Random numbers play an essential role in guaranteeing secrecy in most cryptographic systems. A chaotic optical signal is exploited to achieve high-speed random numbers. It could be generated by using one or more semiconductor lasers with external optical feedback. However, this system faces two major issues, high peak to average power ratio (PAPR) and parameter variations. These issues highly affected the randomness of the generated bitstreams. In this paper, we use a non-linear compression technique to compand the generated signal before it is quantized to avoid the effects of the PAPR. Also, we develop the post-processing stage by using advanced encryption standard (AES) algorithm feeds from two different generated bitstreams. These two integrated stages, non-linear quantization, and post-processing are configured to achieve a generation of a efficient random number guaranteed by NIST and DIEHARD statistical test suites. Finally, the proposed system is verified at parameter variation of ±20% tolerance including external mirror reflectivity, external cavity length, and normalized injection current. The results show that the proposed system could generate truly random numbers even with parameters configuration tolerance.