Public key authentication and key agreement for low-cost terminals
First Claim
1. A method for achieving identity verification and session key agreement between first and second parties communicating via a communication medium comprisingtransmitting a challenge in the form of message m from the second party to the first party,at the first party, computing a signature S(m) of message m using an asymmetric signature operation,encrypting at least a part of the signature by performing at the first party a trap door public key operation using a public key of the second party,transmitting the public key encrypted part of the signature and any remaining part of the signature from said first party to said second party,at said second party, decrypting the encrypted part of the signature using a secret key of the second party and verifying said signature,the public key encrypted and decrypted portion of said signature being used as a session key for encrypting messages communicated between said first and second parties.
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Abstract
A method for achieving mutual authentication and session key agreement between a first party 12 which has minimal computational resources and a second party 18 which has substantial computational resources utilizes a modular square root operation for certificate authentication and key distribution and an ElGamal, NIST DSS, or other efficient signature operation for obtaining the signature of a message. Theses operations are highly advantageous in a system with asymmetric resources because the computation power required to perform these operations is far less than the computation power required to invert these operations. The entire mutual authentication and session key agreement method can be carried out using only between one and three modular multiplications on the weak computational side.
161 Citations
14 Claims
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1. A method for achieving identity verification and session key agreement between first and second parties communicating via a communication medium comprising
transmitting a challenge in the form of message m from the second party to the first party, at the first party, computing a signature S(m) of message m using an asymmetric signature operation, encrypting at least a part of the signature by performing at the first party a trap door public key operation using a public key of the second party, transmitting the public key encrypted part of the signature and any remaining part of the signature from said first party to said second party, at said second party, decrypting the encrypted part of the signature using a secret key of the second party and verifying said signature, the public key encrypted and decrypted portion of said signature being used as a session key for encrypting messages communicated between said first and second parties.
Specification