Hardware Based Cryptography

• US 20100322418A1
• Filed: 06/17/2009
• Published: 12/23/2010
• Est. Priority Date: 06/17/2009
• Status: Active Grant

• Current Assignee: Empire Technology Development LLC (Allied Inventors Management, LLC), Regents of the University of California (University of California)
• Original Assignee: Empire Technology Development LLC (Allied Inventors Management, LLC)
• Inventors: Potkonjak, Miodrag
• Granted Patent: US 8,379,856 B2
• Time in Patent Office: Days
• US Class Current: 380/255
• CPC Class Codes: H04L 2209/12 Details relating to cryptographic hardware or logic circuitry
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/80 Wireless
• CPC Class Codes: H04L 9/0866 involving user or device identifiers, e.g. serial number, physical or biometrical information, DNA, hand-signature or measurable physical characteristics

Abstract

Technologies are generally described for a hardware cryptographic unit that employs hardware public physically unclonable functions. A source computer can encrypt a message using a simulation of a hardware cryptographic unit. The encrypted message can then be sent to a destination computer. The destination computer can then use the hardware cryptographic unit to decrypt the message. The source computer can use a simulation of the hardware cryptographic unit to transform an input value into a simulation output. The simulation output can be transmitted from the source computer to the destination computer where all possible input values can be rapidly run through the hardware cryptographic unit until the output of the hardware cryptographic unit matches the simulated output. The input value that generated the matching output is now a shared secret between the source computer and destination computer without ever having been transmitted in the clear over the communication channel.

Claims

1. A method for exchanging a shared secret using a hardware public physically unclonable function, the method comprising:

receiving encrypted data;

loading at least one of a pool of possible initial values into an input register associated with the hardware public physically unclonable function;

coupling logic signals corresponding to the loaded values from the input register into the hardware public physically unclonable function;

propagating the logic signals through the hardware public physically unclonable function so as to generate a second set of logic signals from the coupled logic signals;

latching the second set of logic signals from the hardware public physically unclonable function into an output register;

comparing the latched output register with the received encrypted data; and

identifying the loaded initial value as the shared secret in response to the latched output register matching the received encrypted data.

2. The method of claim 1, further comprising initializing the input register to a known state prior to loading the initial values.

3. The method of claim 1, wherein the hardware public physically unclonable function comprises a plurality of logic gates.

4. The method of claim 1, wherein the hardware public physically unclonable function comprises nanowires.

5. The method of claim 1, wherein the hardware public physically unclonable function comprises photonic crystals.

6. The method of claim 1, further comprising receiving an encrypted message and decrypting the encrypted message by combining the encrypted message with the shared secret.

7. The method of claim 1, further comprising configuring the input to a stream cipher using the shared secret.

8. A computer storage medium having computer-executable instructions stored thereon which, when executed by a computer, configure the computer to share a secret input value by:

selecting the input value from a pool of input values;

receiving information characterizing unique parameters associated with a hardware public physically unclonable function;

simulating the hardware public physically unclonable function based on the information characterizing unique parameters to generate a simulated output from the selected input value; and

transmitting the simulated output to the hardware public physically unclonable function where the selected input value can be recovered.

9. The computer storage medium of claim 8, wherein the selected input value and the recovered selected input value comprise a shared secret between the computer system and the system associated with the hardware public physically unclonable function.

10. The computer storage medium of claim 9, further comprising causing the computer system to combine the shared secret with a plaintext message to generate a ciphertext message to be transmitted to the system associated with the hardware public physically unclonable function.

11. The computer storage medium of claim 9, wherein the shared secret is an input to a stream cipher.

12. The computer storage medium of claim 9, wherein the shared secret supports decrypting messages received from the system associated with the hardware public physically unclonable function.

13. The computer storage medium of claim 9, wherein the shared secret supports a secure key exchange between the computer system and the system associated with the hardware public physically unclonable function.

14. A cryptographic system comprising:

a hardware public physically unclonable function having operational characteristics capable of being parameterized, wherein the parameters are related to manufacturing variability within the hardware public physically unclonable function;

an input register for loading signals into the hardware public physically unclonable function;

an output register for delivering result values from the hardware public physically unclonable function; and

a search module operable to search an input space by loading elements of the input space into the input register and identifying a desired result at the output register.

15. The cryptographic system of claim 14, further comprising a timing mechanism for determining when the result values are latched at the output register.

16. The cryptographic system of claim 14, further comprising an interface to a host computer, the interface configured to communicate with the search module.

17. The cryptographic system of claim 14, wherein the hardware public physically unclonable function operates with a time less than a time used for simulating the hardware public physically unclonable function from the parameterized characteristics.

18. The cryptographic system of claim 14, wherein the hardware public physically unclonable function comprises a plurality of logic gates.

19. The cryptographic system of claim 14, wherein the hardware public physically unclonable function comprises nanowires.

20. The cryptographic system of claim 14, wherein the hardware public physically unclonable function comprises photonic crystals.