Method of confirming a secure key exchange

• US 20060245590A1
• Filed: 06/30/2006
• Published: 11/02/2006
• Est. Priority Date: 06/18/2002
• Status: Abandoned Application

• Current Assignee: Tahoe Research Limited (f/k/a Learndale Limited) (Vector Capital Corporation)
• Original Assignee: Tahoe Research Limited (f/k/a Learndale Limited) (Vector Capital Corporation)
• Inventors: Brickell, Ernie F.
• Application Number:
  US11/479,747
• Publication Number:
  US 20060245590A1
• Time in Patent Office: Days
• US Class Current: 380/44
• CPC Class Codes: G06F 21/85 interconnection devices, e.g. bus-connected or in-line devices
• CPC Class Codes: H04L 2463/062 applying encryption of the keys cryptographic mechanisms or cryptographic arrangements for key distribution using key encryption key H04L9/0822
• CPC Class Codes: H04L 63/061 for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838
• CPC Class Codes: H04L 63/1466 Active attacks involving interception, injection, modification, spoofing of data unit addresses, e.g. hijacking, packet injection or TCP sequence number attacks
• CPC Class Codes: H04L 9/0841 involving Diffie-Hellman or related key agreement protocols

Abstract

A key exchange protocol can be performed between components of a system, such as between a computer program being executed by the processor of a PC (or other computer system) and a peripheral. A peripheral with a user input capability and a very limited display capability, such as a keyboard or a mouse, may be used to confirm a key exchange between the system components in a way that requires the user to enter only small amounts of input data (e.g., keystrokes or mouse clicks). Security between components may be enhanced without having a negative impact on usability of the system. Embodiments of the present invention help to deter “man in the middle” attacks wherein an attacker gains control of a system component situated between certain communicating system components.

Claims

1. A method of securely exchanging a symmetric key between first and second components of a system comprising:

performing a public key exchange to share a symmetric key;

committing, by the first component, to a first value;

securely exchanging a shared secret between the first component and the second component;

disclosing, by the first component, the first value; and

verifying, by the second component, the correctness of the first component'"'"'s commitment.

2. The method of claim 1, further comprising:

committing, by the second component, to a second value;

disclosing, by the second component, the second value; and

verifying, by the first component, the correctness of the first component'"'"'s commitment.

3. The method of claim 1, wherein the first value comprises a value computed from the shared secret, a random nonce, and a public key of the first component used in the key exchange.

4. The method of claim 1, wherein the first value comprises a value computed from the shared secret, a random nonce, and the symmetric key derived from the key exchange.

5. The method of claim 2, wherein the second value comprises a value computed from the shared secret, a random nonce, and the symmetric key derived from the key exchange.

6. The method of claim 2, wherein the second value comprises a value computed from the shared secret, a random nonce, and a public key of the second component used in the key exchange.

7. An article comprising:

a machine accessible medium having a plurality of machine accessible instructions, wherein when the instructions are executed by a processor, the instructions provide for securely exchanging a symmetric key between first and second components of a system, the instructions including performing a public key exchange to share a symmetric key;

committing, by the first component, to a first value;

securely exchanging a shared secret between the first component and the second component;

disclosing, by the first component, the first value; and

verifying, by the second component, the correctness of the first component'"'"'s commitment.

8. The article of claim 7, further comprising instructions for committing, by the second component, to a second value;

disclosing, by the second component, the second value; and

verifying, by the first component, the correctness of the first component'"'"'s commitment.

9. The article of claim 7, wherein the first value comprises a value computed from the shared secret, a random nonce, and a public key of the first component used in the key exchange.

10. The article of claim 7, wherein the first value comprises a value computed from the shared secret, a random nonce, and the symmetric key derived from the key exchange.

11. The article of claim 8, wherein the second value comprises a value computed from the shared secret, a random nonce, and the symmetric key derived from the key exchange.

12. The article of claim 8, wherein the second value comprises a value computed from the shared secret, a random nonce, and a public key of the second component used in the key exchange.