Cellular authentication for authentication to a service

1. A method of operating an identification system, the method comprising:

receiving from a mobile device a registration request to initiate an access session between the mobile device and a communication network, wherein the registration request comprises a device identifier that identifies the mobile device;

in response to the registration request, transferring a packet address to the mobile device, wherein the mobile device transfers a service request for a service on the communication network during the access session, wherein the service request includes the packet address;

receiving an identification request transferred from an authentication system in response to the service request, wherein the identification request indicates the packet address;

in response to the identification request, transferring the device identifier for delivery to the authentication system to authenticate the mobile device for the service using the device identifier.

2. The method of claim 1 wherein the service, in response to receiving the service request for the service from the mobile device during the access session, transfers an authentication request for the service to the mobile device.

3. The method of claim 2 wherein the mobile device, in response to receiving the authentication request, transfers the service request to the authentication system, wherein the service request includes the packet address.

4. The method of claim 1 wherein the authentication system, to authenticate the mobile device for the service using the device identifier, determines a user identifier associated with the service based on the device identifier, encrypts an authentication assertion comprising the user identifier, and transfers the authentication assertion to the mobile device.

5. The method of claim 4 wherein the authentication system encrypts the authentication assertion using a private key.

6. The method of claim 4 wherein the mobile device, in response to receiving the authentication assertion, transfers the authentication assertion to the service, and wherein the service decrypts the authentication assertion to recover the user identifier and verifies the user identifier to authenticate the user of the mobile device requesting the service.

7. The method of claim 6 wherein the service decrypts the authentication assertion using a public key.

8. The method of claim 1 wherein the service comprises a website.

9. An identification system comprising:

a communication interface configured to receive from a mobile device a registration request to initiate an access session between the mobile device and a communication network, wherein the registration request comprises a device identifier that identifies the mobile device,

in response to the registration request, the communication interface configured to transfer a packet address to the mobile device, wherein the mobile device transfers a service request for a service on the communication network during the access session, wherein the service request includes the packet address,

the communication interface configured to receive an identification request transferred from an authentication system in response to the service request, wherein the identification request indicates the packet address, and

in response to the identification request, the communication interface configured to transfer the device identifier for delivery to the authentication system to authenticate the mobile device for the service using the device identifier.

10. The system of claim 9 wherein the service, in response to receiving the service request for the service from the mobile device during the access session, transfers an authentication request for the service to the mobile device.

11. The system of claim 9 wherein the mobile device, in response to receiving the authentication request, transfers the service request to the authentication system, wherein the service request includes the packet address.

12. The system of claim 9 wherein the authentication system, to authenticate the mobile device for the service using the device identifier, determines a user identifier associated with the service based on the device identifier, encrypts an authentication assertion comprising the user identifier, and transfers the authentication assertion to the mobile device.

13. The system of claim 12 wherein the authentication system encrypts the authentication assertion using a private key.

14. The system of claim 12 wherein the mobile device, in response to receiving the authentication assertion, transfers the authentication assertion to the service, and wherein the service decrypts the authentication assertion to recover the user identifier and verifies the user identifier to authenticate the user of the mobile device requesting the service.

15. The system of claim 14 wherein the service decrypts the authentication assertion using a public key.

16. The system of claim 9 wherein the service comprises a website.

17. A method of operating a communication system, the method comprising:

in a mobile device, transferring a registration request to an identification system to initiate an access session between the mobile device and a communication network, wherein the registration request comprises a device identifier that identifies the mobile device;

in the identification system, in response to the registration request, transferring a packet address to the mobile device;

in the mobile device, transferring a service request for a service on the communication network during the access session, wherein the service request includes the packet address;

in the service, in response to the service request, transferring an authentication request for the service to the mobile device;

in the mobile device, upon receiving the authentication request, transferring the service request to an authentication system, wherein the service request includes the packet address;

in the authentication system, receiving the service request transferred from the mobile device, and, in response to the service request, transferring an identification request to the identification system, wherein the identification request indicates the packet address;

in the identification system, receiving the identification request transferred from the authentication system, determining the device identifier associated with the packet address indicated in the identification request, and transferring the device identifier to the authentication system;

in the authentication system, determining a user identifier associated with the service based on the device identifier, encrypting an authentication assertion comprising the user identifier, and transferring the authentication assertion to the mobile device;

in the mobile device, receiving the authentication assertion transferred from the authentication system, and transferring the authentication assertion to the service; and

in the service, decrypting the authentication assertion to recover the user identifier, and verifying the user identifier to authenticate a user of the mobile device requesting the service.

18. The method of claim 17 wherein, in the authentication system, encrypting the authentication assertion comprises encrypting the authentication assertion using a private key.

19. The method of claim 17 wherein, in the service, decrypting the authentication assertion to recover the user identifier comprises decrypting the authentication assertion using a public key.

20. The method of claim 17 wherein, in the service, verifying the user identifier to authenticate the user of the mobile device requesting the service comprises verifying the user identifier matches one of a plurality of user identifiers associated with known users of the service.