An overview of hybrid random number generators

The generation of random numbers is a important topic in cryptography. Random number generators are bradly divided into two categories: random number generators(RNGs) and pseudo-random number generators(PRNGs). If the PRNGs werw intensively studied in the specialized literature, many such generators being built and analyzed, the topic of RNGs did not capture the researchers atention so much. Candidates in this first category generate nondeterministic sequences and are often based on physical reactions, such as radioactive degradation or mouse movement. A special category of generators is the one that combines the two categories, namely, the category of hybrid generators (HRGs). The purpose of this paper is to study in detail the category of hybrid generators and to provide a detailed analysis of the results of statistical tests, security , portability and how to improve some of the generators of this category.