True random number generators in modern cryptography: A review

With the explosive progress in electronic communication and the widespread use of networks, information security has become increasingly important to people from every aspect of life. Random numbers are sets of numerals arranged so that the values in the sequence are evenly distributed and independent of one another. Due to randomness, random numbers are used by many industries to produce random sets. There are vast industries such as financial institutions, gaming, secure networks, cybersecurity, and others. Over the recent years, as hardware technology advanced, random number generation became an appealing research subject, drawing a lot of effort from the research community worldwide. The random number generators are mainly classified as true random number generators and Pseudo-random number generators. True random numbers have better randomness and unpredictability in encryption and keys than pseudorandom numbers. The starting sections give a brief idea of security and the different types of attacks on it. Then, different hardware security preventive measures are discussed. This paper aims to deliver a methodical review of true random number generators (TRNGs). The main part of TRNG is to select an appropriate source of randomness and designs that are exposed to assist researchers in choosing the ones that best suit their needs and goals. The existing TRNG designs were reviewed, highlighting their role and their impact on the field. We also devote a part of the paper to reviewing different technology-based TRNGs and what parameters are required to design appropriate true random number generators.