Symmetrization of single-sided or nonsymmetrical distributions: The way to enhance a generation rate of random bits from a physical source of randomness

An efficient method for enhancement of a random bit generation rate from a physical source of randomness is proposed. It is based on the repeated application of the operation of symmetrization of random data. This procedure allows one to transform asymptotically any nonsymmetrical distribution into a perfectly symmetrical one. As a result, one can extract up to 46 uncorrelated and unbiased bits from each variate, increasing an effective rate up to 46 times with respect to the mean frequency of random events. The method was tested with spontaneous switchings in a bistable vertical cavity laser. A statistical analysis of the generated random bit sequences which passed the standard randomness tests (ENT, NIST Statistical Test Suites, and Diehard) is presented.