METHOD AND SYSTEM FOR ENHANCING CRYPTOGRAPHIC CAPABILITIES OF A WIRELESS DEVICE USING BROADCASTED RANDOM NOISE

• US 20080089518A1
• Filed: 10/12/2007
• Published: 04/17/2008
• Est. Priority Date: 10/12/2006
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Briancon, Alain, Cha, Inhyok, Reznik, Alexander, Shah, Yogendra, Ye, Chunxuan, DiFazio, Robert, Dodis, Yevgeniy
• Granted Patent: US 8,254,574 B2
• Time in Patent Office: Days
• US Class Current: 380/268
• CPC Class Codes: H04L 2209/08 Randomization, e.g. dummy operations or using noise
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 63/0457 wherein the sending and receiving network entities apply dynamic encryption, e.g. stream encryption cryptographic mechanisms or cryptographic arrangements for stream encryption H04L9/065
• CPC Class Codes: H04L 9/065 Encryption by serially and continuously modifying data stream elements, e.g. stream cipher systems, RC4, SEAL or A5/3
• CPC Class Codes: H04L 9/0869 involving random numbers or seeds
• CPC Class Codes: H04L 9/0875 based on channel impulse response [CIR]
• CPC Class Codes: H04W 12/033 of the user plane, e.g. user's traffic
• CPC Class Codes: H04W 12/041 Key generation or derivation

Abstract

A secret stream of bits begins by receiving a public random stream contained in a wireless communication signal at a transmit/receive unit. The public random stream is sampled and specific bits are extracted according to a shared common secret. These extracted bits are used to create a longer secret stream. The shared common secret may be generated using JRNSO techniques, or provided to the transmit/receive units prior to the communication session. Alternatively, one of the transmit/receive unit is assumed to be more powerful than any potential eavesdropper. In this situation, the powerful transmit/receive unit may broadcast and store a public random stream. The weaker transmit/receive unit selects select random bits of the broadcast for creating a key. The weaker transmit/receive unit sends the powerful transmit/receive unit the selected bit numbers, and powerful transmit/receive unit uses the random numbers to produce the key created by the weaker transmit/receive unit.

Claims

1. A method implemented in a transmit/receive unit for generating a secret stream of data based on received random public noise, the method comprising:

receiving a random public noise stream;

sampling the random public noise stream using a short secret key;

extracting a long secret based on the sampling; and

transmitting encrypted data using the long secret for encryption.

2. The method of claim 1 wherein the sampling is performed for a period of time long enough to exceed the storage limit of an attacker.

3. The method of claim 1 wherein the short secret key is generated using a joint randomness not shared with others (JRNSO) process.

4. The method of claim 3 wherein the JRNSO process utilizes the random public noise stream.

5. The method of claim 1 wherein the short secret key is stored on a universal subscriber identity module (USIM).

6. The method of claim 5 wherein the USIM expires when the entire short secret key has been used for sampling.

7. The method of claim 1 wherein the short secret key is preprogrammed into a transmit/receive terminal.

8. The method of claim 1 wherein the short secret key is provided when located in a secure area.

9. The method of claim 1 wherein transmitting encrypted data includes transmitting the encrypted data to more than two transmit/receive units.

10. The method of claim 1 wherein public randomness stream is transmitted by a base station in a cellular network.

11. The method of claim 1 wherein the public randomness stream is transmitted as part of a second wireless communication system.

12. A wireless transmit/receive unit (WTRU) for transmitting and receiving encrypted data using public random noise;

the WTRU comprising;

a receiver for receiving random public noise;

a processor for sampling the random public noise based on a short secret key, and for extracting a long secret based on the sampling; and

a transmitter for transmitting data encrypted using the long secret.

13. The WTRU of claim 12 wherein the receiver is further configured to receive encrypted data, and the processor is further configured to decrypt the received encrypted data using the long secret.

14. The WTRU of claim 12 wherein the short secret key is generated using a joint randomness not shared with others (JRNSO) process which utilizes the random public noise.

15. The WTRU of claim 12 wherein the short secret key is stored on a universal subscriber identity module (USIM).

16. The WTRU of claim 15 wherein the USIM expires when the entire short secret key has been used for sampling.

17. The WTRU of claim 12 wherein the random public noise is received from a base station.

18. The WTRU of claim 12 wherein the random public noise is received from part of a second type of wireless communication system.

19. The WTRU of claim 12 wherein the short secret key is provided to the WTRU over a secure network prior to disassociating with the secure network.

20. A method, implemented in a transmit/receive unit, of generating an encrypted stream of data between a first and second transmit/receive unit, wherein the second transmit/receive unit has very large storage capacity, the method comprising:

transmitting a public stream of random noise;

storing said public stream of random noise;

receiving random numbers from the first transmit/receive unit;

generating a long key from said stored public stream of random noise using said random numbers; and

transmitting an encrypted stream of data using the long key.

21. The method of claim 20 further comprising:

receiving an encrypted stream of data using the long key.

22. The method of claim 20 wherein the second transmit receiving unit is a base station.

23. A method, implemented in a transmit/receive unit, of generating an encrypted stream of data between a first and second transmit/receive unit, wherein the second transmit/receive unit has very large storage capacity, the method comprising:

receiving a public stream of random noise;

generating random numbers;

selectively storing bits from the public stream of random noise based on the random numbers to create a long key;

transmitting random numbers to the second transmit/receive unit; and

transmitting an encrypted stream of data using the long key.

24. The method of claim 23 further comprising:

receiving an encrypted stream of data using the long key.

25. The method of claim 23 wherein the public stream of random noise is received from an entity other than the second transmit/receive unit.