Identity based authenticated key agreement protocol

A method for obtaining authenticated key agreement 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:

• computing a first random key component at the first party;
• encrypting at the first party the first random key component, wherein the first random key component is encrypted using a public key of the second party in accordance with an identity based encryption operation;
• sending the encrypted first random key component to the second party, wherein, at the second party:
• (i) the encrypted first random key component is decrypted to obtain the first random key component;
• (ii) a second random key component is computed;
• (iii) a random key component pair comprising the first random key component and the second random key component is formed and encrypted using a public key of the first party in accordance with the identity based encryption operation;
• and (iv) the encrypted random key component pair is sent to the first party;
• decrypting at the first party the encrypted random key component pair to obtain the second random key component;
• encrypting at the first party the second random key component, wherein the second random key component is encrypted using the public key of the second party in accordance with the identity based encryption operation;
• sending the encrypted second random key component to the second party;
• and
• computing at the first party a key for use in subsequent communications between the first party and the second party, wherein the key is computed at the first party based on the second random key component, and wherein the key is computable at the second party based on the first random key component.

A method for performing an identity based authenticated key agreement protocol 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 from the first party at 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;
• sending an encrypted random key component pair to the first party from the second party, the random key component pair having been encrypted at the second party using a public key of the first party in accordance with the identity based encryption operation, and the random key component pair having been formed from the first random key component and a second random key component computed at the second party;
• and
• receiving the second random key component, in encrypted form, from the first party at 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;
• wherein a key for use in subsequent communications between the first party and the second party is computable at the second party based on the first random key component.

A method for obtaining authenticated key agreement 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 at the second party from the first party, wherein, at the first party:
• (i) the first random key component is computed;
• (ii) the first random key component is encrypted using a public key of the second party in accordance with an identity based encryption operation;
• and (iii) the encrypted first random key component is sent to the second party;
• decrypting the encrypted first random key component to obtain the first random, key component;
• computing a second random key component;
• forming a random key component pair comprising the first random key component and the second random key component;
• encrypting the random key component pair using a public key of the first party in accordance with the identity based encryption operation;
• sending the encrypted random key component pair to the first party, wherein, at the first party:
• (i) the encrypted random key component pair is decrypted to obtain the second random key component;
• (ii) the second random key component is encrypted using the public key of the second party in accordance with the identity based encryption operation, and (iii) the encrypted second random key component is sent to the second party;
• and
• computing at the second party a key for use in subsequent communications between the first party and the second party, wherein the key is computed at the second party based on the first random key component, and wherein the key is computable at the first party based on the second random key component.

Apparatus for performing an identity based authenticated key agreement protocol between a first party and a second party, the apparatus at the first party comprising:

• a memory;
• and
• a processor coupled to the memory and configured to:
• (i) send an encrypted first random key component from the first party 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;
• (ii) receive an encrypted random key component pair at the first party from the second party, the random key component pair having been encrypted at the second party using a public key of the first party in accordance with the identity based encryption operation, and the random key component pair having been formed from the first random key component and a second random key component computed at the second party;
• and (iii) send the second random key component, in encrypted form, from the first party 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;
• wherein a key for use in subsequent communications between the first party and the second party is computable at the first party based on the second random key component.

Apparatus for performing an identity based authenticated key agreement protocol between a first party and a second party, the apparatus at the second party comprising:

• a memory;
• and
• a processor coupled to the memory and configured to:
• (i) receive an encrypted first random key component from the first party at 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;
• (ii) send an encrypted random key component pair to the first party from the second party, the random key component pair having been encrypted at the second party using a public key of the first party in accordance with the identity based encryption operation, and the random key component pair having been formed from the first random key component and a second random key component computed at the second party;
• and (iii) receive the second random key component, in encrypted form, from the first party at 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;
• wherein a key for use in subsequent communications between the first party and the second party is computable at the second party based on the first random key component.