US 6,651,167 B1 · Authentication method and system employing secret functions in finite Abelian group

Abstract

A method and a system for authentication whereby authentication characteristic information is not disclosed to a third party when a verifier uses a verification device of a limited scale to authenticate a user's rights or qualifications. A ticket issuing device interacts with the user's interactive device having a secret function f to calculate document secret information μ based on a document m (data) to be transmitted to the interactive device, whereby the user is issued a ticket t generated from authentication characteristic information x and the document secret information π. Upon receipt of the document m, the interactive device generates the document secret information using its unique secret function f to perform an interaction based on the generated information. The interaction involves output of a commitment r, input of a challenge c, and an output of a response σ. The user converts the interaction (r, c, σ) into another interaction (r, c, s) using the ticket t to effect Guillou-Quisquater authentication.

Claims24

Dependent claims

An authentication method in effect where p stands for a prime number, Fp for the finite field with p-elements, G for a finite Abelian group whose annihilator is difficult to obtain in terms of computational complexity, D for a space of commitments, and π for a map from G to D, wherein a commitment rεD is generated and a response sεG is created in reply to a document m and a challenge cεFp so that authentication is performed in accordance with authentication information IεG, the commitment r and the response s, said authentication method comprising the steps of:

(a) randomizing nonreproducible secret information kεG;
(b) calculating the commitment r=π(kp);
(c) calculating document secret information μ=f(m) where f denotes a secret function valued in said finite Abelian group G;
(d) calculating a support response σ=kμc;
(e) inputting authentication support information t=xμ−1 generated on the basis of both authentication characteristic information xεG satisfying Ixp=1 where I denotes verification information, and the document secret information μ;
(f) inputting the challenge cεFp;
(g) generating the response s=σtc based on the challenge c, authentication support information t and support response σ;
and
(h) verifying that the generated response s satisfies r=π(spIc).

6 more elements

Dependencies are inferred from the claim text.

Authentication method and system employing secret functions in finite Abelian group

Life of this patent

Authentication method and system employing secret functions in finite Abelian group

Life of this patent

Abstract

Claims24