Terminal authentication in a wireless network

• US 7,499,548 B2
• Filed: 06/24/2003
• Issued: 03/03/2009
• Est. Priority Date: 06/24/2003
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Dogan, Mithat Can, Meandzija, Branislav N., Goldburg, Marc C., Uhlik, Christopher R.
• Primary Examiner(s): Vu; KimYen
• Assistant Examiner(s): PATEL, NIRAV B
• Application Number:
  US10/603,424
• Publication Number:
  US 20040264699A1
• Time in Patent Office: 2,079 Days
• Field of Search: 713/156, 713/181, 713168-170, 713/175, 713/178, 380/270, 380/268, 380/255, 380 28- 30, 726/2, 726/27, 726/21, 726/30, 455/410, 455/411
• US Class Current: 380/270
• CPC Class Codes: H04L 2209/80 Wireless
• CPC Class Codes: H04L 63/0407 wherein the identity of one or more communicating identities is hidden cryptographic mechanisms or cryptographic arrangements for anonymous credentials or for identity based cryptographic systems H04L9/00
• CPC Class Codes: H04L 63/0435 wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 9/3263 involving certificates, e.g. public key certificate [PKC] or attribute certificate [AC]; Public key infrastructure [PKI] arrangements network architectures or network communication protocols for supporting authentication of entities using certificates in a packet data network H04L63/0823
• CPC Class Codes: H04W 12/02 Protecting privacy or anonymity, e.g. protecting personally identifiable information [PII]
• CPC Class Codes: H04W 12/06 Authentication
• CPC Class Codes: H04W 12/50 Secure pairing of devices
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A user terminal can be authenticated by an access point based on one message. In one embodiment, the present invention includes the access point receiving a message containing a shared secret encrypted with an access point public key, a user terminal certificate, and an authenticator string demonstrating possession by the user terminal of a user terminal private key. The access point can decrypt the shared secret using the private key of the access point paired with its private key. The access point can then authenticate the user terminal by checking the authenticator string using a user terminal public key included in the user terminal certificate to verify possession of the user terminal private key by the user terminal.

Claims

1. A method performed by a user terminal of a wireless access network, the method comprising:

generating a shared secret to be provided to an access point of the wireless access network;

encrypting the shared secret with an access point public key;

pre-calculating a plurality of authenticator messages based on a corresponding plurality of estimated time parameters, each authenticator message comprising at least part of the shared secret;

receiving an indication of a measured time parameter; and

selecting a pre-calculated authenticator message that corresponds to the measured time parameter; and

signing the selected authenticator message with a user terminal private key; and

sending a message to the access point, the message including the encrypted shared secret, a user terminal certificate, and the signed authenticator message.

2. The method of claim 1, wherein the user terminal certificate is scrambled, using a pseudo-random sequence generator initialized with a part of the shared secret, before being included in the message.

3. The method of claim 2, wherein the remainder of the shared secret comprises a master secret to be used for symmetric key cryptography between the user terminal and the access point.

4. The method of claim 1, wherein signing the authenticator message comprises:

generating a digest of the authenticator message; and

encrypting the authenticator message digest with the user terminal private key.

5. The method of claim 1, wherein the estimated time parameters comprise absolute frame numbers and the measured time parameter comprises an absolute frame number.

6. The method of claim 1, wherein the user terminal generates and encrypts the shared secret prior to identifying the access point by encrypting the shared secret with the public keys of a plurality of access points stored in the user terminal.

7. A user terminal comprising:

a memory to store a user terminal certificate and a shared secret to be provided to an access point;

a processor coupled to the memory to

encrypt the shared secret with access point public key,

pre-calculate a plurality of authenticator messages based on a corresponding plurality of estimated time parameters, each authenticator message comprising at least part of the shared secret;

receive an indication of a measured time parameter,

select a pre-calculated authenticator message that corresponds to the measure time parameter, and

sign the selected authenticator message with a user terminal private key; and

a transmitter coupled to the processor to send a message to the access point, the message including the encrypted shared secret, the user terminal certificate, and the signed authenticator message.

8. The user terminal of claim 7, wherein the processor is further to scramble the user terminal certificate using a pseudo-random sequence generator initialized with a part of the shared secret, before being included in the message.

9. The user terminal of claim 8, wherein the remainder of the shared secret comprises a master secret to be used for symmetric key cryptography between the user terminal and the access point.

10. The user terminal of claim 7, wherein signing the authenticator message comprises:

generating a digest of the authenticator message; and

encrypting the authenticator message digest with the user terminal private key.

11. The user terminal of claim 7, wherein the estimated time parameters comprise absolute frame numbers and the measured time parameter comprises an absolute frame number.

12. A machine-readable medium storing data representing instructions that, when executed by a processor of a user terminal, cause the processor to perform operations comprising:

generating a shared secret to be provided to an access point of the wireless access network;

encrypting the shared secret with an access point public key;

pre-calculating a plurality of authenticator messages based on a corresponding plurality of estimated time parameters, each authenticator message comprising at least part of the shared secret;

receiving an indication of a measured time parameter; and

selecting a pre-calculated authenticator message that corresponds to the measured time parameter; and

signing the selected authenticator message with a user terminal private key; and

sending a message to the access point, the message including the encrypted shared secret, a user terminal certificate, and the signed authenticator message.

13. The machine-readable medium of claim 12, wherein the user terminal certificate is scrambled, using a pseudo-random sequence generator initialized with a part of the shared secret, before being included in the message.

14. The machine-readable medium of claim 13, wherein the remainder of the shared secret comprises a master secret to be used for symmetric key cryptography between the user terminal and the access point.

15. The machine-readable medium of claim 12, wherein signing the authenticator message comprises:

generating a digest of the authenticator message; and

encrypting the authenticator message digest with the user terminal private key.

16. The machine-readable medium of claim 12, wherein the estimated time parameters comprise absolute frame numbers and the measure time parameter comprises an absolute frame number.