Patent ID: 8782391

Claim:
A method comprising: identifying, at an issuer computer, a user who is authorized to enroll in a service based on issuer-specified criteria established by an issuer associated with the issuer computer; retrieving, by the issuer computer, data associated with the user and a shared data element shared between the issuer computer and a service provider computer; generating a first activation code by the issuer computer, the first activation code based on the data associated with the user and the shared data element, wherein generating the first activation code includes: creating a text block containing the data associated with the user; appending the shared data element to the text block; processing the text block with a hashing algorithm, to generate the first activation code; and appending a version identifier that specifies a version of the shared data element to the first activation code; and sending the first activation code to the user, wherein the user sends the first activation code and the data associated with the user to the service provider computer, the service provider computer generates a second activation code based on the data associated with the user and the shared data element, and the service provider computer authorizes the user to enroll in the service if the first and second activation codes are the same.