Efficient methods for generating approximately equiprobable random bits

The problem of random number generation is well-known in information theory and investigated by a number of authors due to its great importance for cryptology, Monte-Carlo methods and other applications. The problem of generating almost equiprobable bits from arbitrary but known source was set up and investigated by previous authors. But the proposed methods require exponential growth of the necessary memory size. In this article we propose the methods for generation of almost equiprobable random bits which are based on efficient algorithms of arithmetic coding for known and unknown sources. Complexity of the suggested methods is less in order of magnitude than that for known exact and approximate methods.