Patent ID: 8260722

Claim:
A method comprising: determining, by a computer based system for generating a truncated unpredictable number to facilitate securing a transaction and based upon at least one of an account issuer or a merchant system, a proposed maximum value for an unpredictable number; performing, by the computer based system, a secure hashing algorithm on variable data to produce a message digest, wherein the secure hashing algorithm is configured to produce a digest of at least 16 bytes; selecting, by the computer based system, at least one of a left-most 16 bytes or a right-most 16 bytes of the message digest to form a random 16-byte value; creating, by the computer based system, the unpredictable number using the random 16-byte value as an input for a seeded pseudo-random number generator; truncating, by the computer based system, the unpredictable number to create the truncated unpredictable number, wherein the truncated unpredictable number is limited to the proposed maximum value; and sending, by the computer based system, the truncated unpredictable number and a cryptogram to an account issuer, wherein the account issuer validates the cryptogram and verifies that the cryptogram includes the truncated unpredictable number.