Identity based authenticated key agreement protocol

1. A method for performing identity based encryption adapted to a communications session between a computer system of a first party (the first party) and a computer system of a second party (the second party), the method at the first party comprising the steps of:

sending an encrypted first random key component directed to the second party, the first random key component having been computed at the first party and encrypted using a public key of the second party in accordance with an identity based encryption operation;

receiving an encrypted second random key component corresponding to the second party;

decrypting the encrypted second random key component using a private key of the first party; and

computing a session key for use in subsequent communications between the first party and the second party based at least in part on the second random key component.

2. The method of claim 1 , wherein the second random key component is received as part of an encrypted random key component pair that includes the first random key component and decrypting the encrypted second random key component comprises decrypting the encrypted random key component pair.

3. The method of claim 1 , further comprising the step of sending the second random key component, in encrypted form, from the first party directed to the second party, the second random key component having been encrypted using the public key of the second party in accordance with the identity based encryption operation.

4. The method of claim 1 , wherein an elliptic curve used to compute the first random key component is independent of an elliptic curve used for the identity based encryption operation.

5. The method of claim 1 , wherein the first random key component, xP, is computed from a random number x chosen by the first party and a point P of large prime order on an elliptic curve over a finite field.

6. An apparatus for performing identity based encryption adapted to a communications session between a computer system of a first party (the first party) and a computer system of a second party (the second party), comprising:

a processor and a memory communicatively connected to the processor, the processor configured to:

send an encrypted first random key component directed to the second party, the first random key component having been computed at the first party and encrypted using a public key of the second party in accordance with an identity based encryption operation;

receive an encrypted second random key component corresponding to the second party;

decrypt the encrypted second random key component using a private key of the first party; and

compute a session key for use in subsequent communications between the first party and the second party based at least in part on the second random key component.

7. The apparatus of claim 6 , wherein the second random key component is received as part of an encrypted random key component pair that includes the first random key component and decrypting the encrypted second random key component comprises decrypting the encrypted random key component pair.

8. The apparatus of claim 6 , the processor further configured to send the second random key component, in encrypted form, from the first party directed to the second party, the second random key component having been encrypted using the public key of the second party in accordance with the identity based encryption operation.

9. The apparatus of claim 6 , wherein an elliptic curve used to compute the first random key component is independent of an elliptic curve used for the identity based encryption operation.

10. The apparatus of claim 6 , wherein the first random key component, xP, is computed from a random number x chosen by the first party and a point P of large prime order on an elliptic curve over a finite field.

11. A method for performing identity based encryption adapted to a communications session between a computer system of a first party (the first party) and a computer system of a second party (the second party), the method at the second party comprising the steps of:

receiving an encrypted first random key component corresponding to the first party;

decrypting the encrypted first random key component using a private key of the second party;

sending an encrypted second random key component directed to the first party, the second random key component having been computed at the second party and encrypted using a public key of the first party in accordance with an identity based encryption operation; and

computing a session key for use in subsequent communications between the first party and the second party based at least in part on the first random key component.

12. The method of claim 11 , wherein the encrypted second random key component is sent as part of an encrypted random key component pair that includes the encrypted first random key component.

13. The method of claim 11 , further comprising the step of receiving the second random key component, in encrypted form, the second random key component having been encrypted using the public key of the second party in accordance with the identity based encryption operation.

14. The method of claim 11 , wherein an elliptic curve used to compute the second random key component is independent of an elliptic curve used for the identity based encryption operation.

15. The method of claim 11 , wherein the second random key component, yP, is computed from a random number y chosen by the second party and a point P of large prime order on an elliptic curve over a finite field.

16. An apparatus for performing identity based encryption adapted to a communications session between a computer system of a first party (the first party) and a computer system of a second party (the second party), comprising:

a processor and a memory communicatively connected to the processor, the processor configured to:

receive an encrypted first random key component corresponding to the first party;

decrypt the encrypted first random key component using a private key of the second party;

send an encrypted second random key component directed to the first party, the second random key component having been computed at the second party and encrypted using a public key of the first party in accordance with an identity based encryption operation; and

compute a session key for use in subsequent communications between the first party and the second party based at least in part on the first random key component.

17. The apparatus of claim 16 , wherein the encrypted second random key component is sent as part of an encrypted random key component pair that includes the encrypted first random key component.

18. The apparatus of claim 16 , the processor being further configured to receive the second random key component in encrypted form, the second random key component having been encrypted using the public key of the second party in accordance with the identity based encryption operation.

19. The apparatus of claim 16 , wherein an elliptic curve used to compute the second random key component is independent of an elliptic curve used for the identity based encryption operation.

20. The apparatus of claim 16 , wherein the second random key component, yP, is computed from a random number y chosen by the second party and a point P of large prime order on an elliptic curve over a finite field.