Fast hashing function for pseudo-random generator

A method and computer device for generating a pseudo-random value string of N characters for an authentication token. The method partitions a message digest into at least one segment, each segment comprising a number of consecutive bits from the message digest, wherein the segments are consecutive when taken together, such that a first segment begins with the most significant bit and a last segment ends with the least significant bit. For each segment, the method converts the bits to a decimal value, and compares the decimal value to a set of satisfactory values, wherein each entry in the set includes a valid decimal value and a corresponding character representation. When the decimal value matches a valid decimal value in set of satisfactory values and the length of the pseudo-random value is less than N, the method appends the corresponding character representation of the decimal value to the pseudo- random value.