Patent ID: 7912214

Claim:
A method for generating unique personal promotion codes from computing resources of a provider of services, the method comprising the steps of: generating internal promotion codes including a family ID field and a serial ID field comprised of alphanumeric characters; encoding the internal promotion codes into a corresponding series of external promotion codes, comprised of alphanumeric characters, to render the internal promotion codes unintelligible, wherein the step of encoding each internal promotion code into a corresponding external promotion code includes the steps of: converting the alphanumeric characters of the internal promotion codes to integers; calculating a first and a second checksum; converting the integers to a binary array; shifting a binary encoding key according to the second checksum; shifting the binary array according to the first checksum; xoring (bitwise adding modulo 2 ) the shifted binary encoded key and the shifted binary array; converting back the xored binary array to integers; inserting the first checksum and the second checksum into the xored array of integers; converting back the inserted array of integers to alphanumeric characters; thus, obtaining the corresponding external promotion code.