4. The method of claim 1 , wherein the character string is stored as encrypted data.
1. A method for using a unique token in online transactions involving sensitive information to control access to the sensitive information, the method comprising: registering, by a server entity, at least one entity, the registering comprising associating the at least one entity with a subscription level; in response to receipt of the sensitive information from a merchant device, generating, by the server entity, a unique token for use in place of the sensitive information in online transactions, wherein the sensitive information comprises a character string stored as encrypted data; directly associating, by a server entity, a sub-string of a character string with the unique token so that a direct association does not exist between the unique token and the character string, the character string comprising the sensitive information and the sub-string being configured to identify the character string without revealing the sensitive information; and accessing, by a server entity, the character string stored as encrypted data in storage memory using the unique token and the sub-string to retrieve the sensitive information after transmission of a request for the sensitive information from a registered entity associated with a subscription level associated with a privilege to receive the requested sensitive information.