Authenticating an Ephemeral Diffie-Hellman using a Trusted Third Party

• US 20130111209A1
• Filed: 10/26/2012
• Published: 05/02/2013
• Est. Priority Date: 10/28/2011
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Daniel Harkins
• Inventors: Harkins, Daniel
• Granted Patent: US 8,750,512 B2
• Time in Patent Office: Days
• US Class Current: 713/171
• CPC Class Codes: H04L 9/0844 with user authentication or key authentication, e.g. ElGamal, MTI, MQV-Menezes-Qu-Vanstone protocol or Diffie-Hellman protocols using implicitly-certified keys
• CPC Class Codes: H04L 9/321 involving a third party or a trusted authority
• CPC Class Codes: H04W 12/02 Protecting privacy or anonymity, e.g. protecting personally identifiable information [PII]
• CPC Class Codes: H04W 12/08 Access security

Abstract

Authentication of parties through a trusted intermediary is described. The standard Ottway-Rees authentication protocol is modified to provide authentication between A and B using intermediary T such that T serves only as an authenticator, and does not participate in the generation of the key shared between A and B.

Claims

1. A method comprising:

transmitting, by a first network device, a plurality of messages including (i) a first message that comprises a first public value encrypted with a first key and (ii) a second message that comprises the first message and a second public value, the second message being encrypted with a second key;

receiving, by the first network device, a third message that comprises (i) a fourth message, (ii) the first public value and (iii) the second public value encrypted with the second key, the fourth message including the first public value and the second public value encrypted with the first key;

transmitting, by the first network device, the fourth message to a second network device;

generating a shared key based on one of the first public value and the second public value.

2. The method of claim 1, wherein the first public value is a Diffie-Hellman public value that comprises a Diffie-Hellman generator raised to a power based on a first private value associated with the second network device modulo a predetermined prime number.

3. The method of claim 2, wherein the second public value is a Diffie-Hellman public value that comprises a Diffie-Hellman generator raised to a power based on a second private value associated with the first network device modulo the predetermined prime number.

4. The method of claim 1, wherein the first public value is equal to g^a mod P, where

“

g”

is equal to a Diffie-Hellman generator.

“

a”

is equal to a first private value produced for and securely stored within the second network device, and

“

P”

is the predetermined prime number.

5. The method of claim 4, wherein the second public value is equal to g^b mod P, where

“

g”

is equal to the Diffie-Hellman generator.

“

b”

is equal to a second private value produced for and securely stored within the first network device, and

“

P”

is the predetermined prime number.

6. The method of claim 2, wherein the first message further comprises an identifier of the second network device, an identifier of the first network device and a session identifier.

7. The method of claim 6, wherein the first message further comprises a first nonce.

8. The method of claim 7, wherein the second message further comprises the identifier of the first network device, the identifier of the second network device, and a second nonce.

9. The method of claim 1, wherein the fourth message further comprises an identifier of the first network device, an identifier of the second network device, a session identifier, a first nonce and a second nonce.

10. The method of claim 9, wherein the third message further comprises the identifier of the first network device, the identifier of the second network device, the session identifier, the first nonce and the second nonce.

11. The method of claim 10, wherein the generating of the shared key is based on the first public value, a private value stored within the first network device and inaccessible to the second network device, the first nonce and the second nonce.

12. The method of claim 1, wherein the first public value is a Diffie-Hellman public value that comprises a Diffie-Hellman generator represented by a point on an elliptic curve multiplied by a first private value associated with the second network device.

13. The method of claim 12, wherein the second public value is a Diffie-Hellman public value that comprises a Diffie-Hellman generator represented by a point on the elliptic curve multiplied by a second private value associated with the first network device.

14. The method of claim 12, wherein the first public value is equal to a*G, a first point of the elliptic curve, where

“

G”

is equal to the Diffie-Hellman generator, the point on the elliptic curve, and

“

a”

is equal to the first private value produced for and securely stored within the second network device.

15. The method of claim 14, wherein the second public value is equal to b*G, a second point on the elliptic curve, where

“

G”

is equal to the Diffie-Hellman generator, the point on the elliptic curve

“

b”

is equal to a second private value produced for and securely stored within the first network device.

16. A method comprising:

transmitting, by a first network device, a plurality of messages including (i) a first message that comprises a hash result of a first public value encrypted with a first key and (ii) a second message that comprises a hash result of a second public value and the first message, the second message being encrypted with a second key;

receiving, by the first network device, a third message third message that comprises the hash result of the first public value, the hash result of the second public value and a fourth message encrypted with the second key, the fourth message including the hash result of the first public value and the hash result of second public value encrypted with the first key;

transmitting, by the first network device, the fourth message to a second network device,

wherein one of the hash result of the first public value and the hash result of the second public value is used to generate a shared key to secure communications with the first network device.

17. A non-transitory computer readable medium including software that, when executed by a processor within a network device, performs operations, comprising:

transmitting a plurality of messages including (i) a first message that comprises a first public value encrypted with a first key and (ii) a second message that comprises the first message and a second public value, the second message being encrypted with a second key;

receiving a third message third message that comprises the first public value, the second public value and a fourth message encrypted with the second key, the fourth message including the first public value and the second public value encrypted with the first key;

transmitting the fourth message to a first network device,

wherein one of the first public value and the second public value is used to generate a shared key to secure communications with the first network device.

18. The computer readable medium of claim 17, wherein the first public value comprises a modulo-based value, the modulo-based value includes a Diffie-Hellman generator raised to a power based on a first private value associated with the first network device modulo a predetermined prime number.

19. The computer readable medium of claim 18, wherein the second public value comprises a modulo-based value includes a Diffie-Hellman generator raised to a power based on a second private value associated with the network device modulo the predetermined prime number.

20. The computer readable medium of claim 17, wherein the first public value is equal to g^a mod P, where

“

g”

is equal to a Diffie-Hellman generator.

“

a”

is equal to a first private value produced for and securely stored within the first network device, and

“

P”

is the predetermined prime number.

21. The computer readable medium of claim 20, wherein the second public value is equal to g^b mod P, where

“

g”

is equal to the Diffie-Hellman generator.

“

b”

is equal to a second private value produced for and securely stored within the network device, and

“

P”

is the predetermined prime number.

22. The computer readable medium of claim 18, wherein the first message further comprises at least two of an identifier of the first network device, an identifier of the network device and a first nonce, and a session identifier.

23. The computer readable medium of claim 22, wherein the second message further comprises at least two of the identifier of the network device, the identifier of the first network device, and a second nonce.

24. The computer readable medium of claim 23 further comprising:

generating the shared key based on the first public value, a private value stored within the network device and inaccessible to the first network device, the first nonce and the second nonce.