Patent ID: 7480803

Claim:
A method for authentication of a requesting entity by an authenticating entity comprising: the requesting entity sending to the authenticating entity a request for data; the authenticating entity retrieving a time data based on a current time of a system of the authenticating entity; the authenticating entity sending the retrieved time data to the requesting entity; the requesting entity returning the retrieved time to the authenticating entity; the authenticating entity determining a received time and calculating a time difference between the retrieved time data and the received time when the retrieved time is received by the authenticating entity; encrypting and decrypting the retrieved time data using a key maintained by both the requesting entity and the authenticating entity, wherein the retrieved time data is encrypted by the requesting entity and decrypted by the authenticating entity, wherein the authenticating entity sending the retrieved time to the requesting entity is performed by sending the retrieved time in plain text, and when the time difference is less than a predetermined threshold, the authenticating entity authenticating the requesting entity.