Cryptographic random and pseudorandom data generators

This dissertation thesis deals with cryptographic random and pseudorandom data generators in mobile computing environments (such as mobile phones, personal digital assistants, cryptographic smartcards). These mobile devices are typically bounded by the amount of energy, performance, memory or even silicon area. This lack of resources leads to very limited computing environments with: a) limited number of sources of randomness for reliable true random data generator; b) limited number of pseudorandom data generators (or other methods of digital post-processing) suitable for secure and efficient implementation (in this mobile environment). In the first chapter we explain the basics of random and pseudorandom data generation for cryptography purposes and also all necessary terminology. The second chapter is organized as a survey of basic requirements on random and pseudorandom data, fundamental results in the field and description of several experiments with cryptographic smartcards. In the last part of this chapter we also discuss a novel idea of distributed random data generation. The third chapter is dedicated to identification and analysis of available sources of randomness in mobile computing environments. The fourth chapter focuses on the secure and efficient digital post-processing of truly random data with the use of randomness extractors or pseudorandom data generators. The fifth chapter presents technical details regarding the integration of our design prototype into selected mobile devices (smartphone Nokia N73 with Symbian OS). The main contribution of this dissertation is the identification and analysis of available sources of randomness in mobile devices, secure integration of selected digital post-processing methods (resulting in a design prototype) and the analysis of approaches to distributed random data generation.