PUBLIC-KEY CRYPTOGRAPHIC SYSTEM AND METHOD FOR THE AUTHENTICATION OF A FIRST ENTITY BY A SECOND ENTITY

摘要

The invention relates to a public-key cryptographic system and method for the authentication of a first entity (E1) possessing a secret key S associated with a public key P by a second entity (E2) possessing said public key P, said secret key S belonging to a first or to a second group (G1, G2) respectively generated by first and second primitives g1 and g2 of prime order q, said method comprising the following steps: sending of a challenge by the second entity (E2) to the first entity (E1); calculation by the first entity (E1) of a response which takes account of said challenge and said secret key S; sending by the first entity (E1) of said response to the second entity; and verification of the response by the second entity (E2) with the aid of said challenge and of the public key P, said public key P comprising, on the one hand, a public value v = e(g1, S) or v = e(S, g2) equal to the image under a bilinear mapping e defined on said first and second groups (G1, G2) of a pair of elements formed by the secret key S and the primitive belonging to the other of the first and second groups (G1, G2) as that to which the secret key S, belongs, and on the other hand, this primitive.