A computer based method, system and apparatus of authentication which compares a first number associated with a user with a second number, wherein the second number is a mathematical function of at least two predetermined digits within the user's identification number, preferably a Social Security Number. A computer based method, system and apparatus for authenticating a user's identification number, which compares a first code associated with a user with a second code, wherein said second code is an alphabetic translation of at least two predetermined digits within the user's identification number.