Patent ID: 11895491
Assignee: VISA INTERNATIONAL SERVICE ASSOCIATION
Field: Digital communication (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 10:
11. The validation entity computer of claim 10,
wherein the first authentication code and the second authentication code each comprise a first portion comprising encrypted information and a second portion comprising unencrypted information, the unencrypted information comprising a key index and the encrypted information including an encrypted account number, a date and time when the authentication data was validated, and an authorization code, and wherein the method further comprises:
locating a key using the key index in the second authentication code;
decrypting the encrypted information in the second authentication code with the key to determine the account number, the date and time when the authentication data was validated, and the authorization code; and
determining that the second authentication code is valid using at least the first authentication code received from the authorization computer system, the authorization code, and the date and time when the authentication data was validated, wherein the key is a symmetric key.