We present, implement and apply a new privacy primitive that we call “Traceable Signatures.” To this end we develop the underlying mathematical and protocol tools, present the concepts and the underlying security model, and then realize the scheme and its security proof. Traceable signatures support an extended set of fairness mechanisms (mechanisms for anonymity management and revocation) when...

The concept of concurrent signatures allows two entities to produce two signatures in such a way that, the signer of each signature is ambiguous from a third party’s point of view until the release of a secret, known as the keystone. Once the keystone is released, both signatures become binding to their respective signers concurrently. Previous concurrent signature schemes use the concept of ri...

This paper presents a novel group signature scheme based on the discrete logarithm problem. In this scheme the length of the signature is independent of the number of members of the group and it supports message recovery feature. In case, some members left the group or joins the group, the group signature remains valid. All valid signatures are traceable by only the group manager. Every member ...

In this paper, we present an improved Rivest’s ring signature scheme. In our scheme, the size of the signature is only related to the ring members, and the signer needs no to publish amount of random numbers. On this basis, we propose a group-oriented ring signature. In this scheme, only the person who belongs to the designated group can verify the validity of the ring signature. The security o...

Abstract With the development of e-commerce, choosing a proper electronic payment method has become more and more important. Competing with other payment methods on the Internet, electronic cash has much more attractive properties, such as anonymity and off-line payment, and is generally considered as an ideal electronic payment method. However, the traceability of the customer or the cash in c...

Ring signature is a group-oriented signature in which the signer can spontaneously form a group and generate a signature such that the verifier is convinced the signature was generated by one member of the group and yet does not know who actually signed. Linkable ring signature is a variant such that two signatures can be linked if and only if they were signed by the same person. Recently, the ...

We present a zero-knowledge argument system of representation of a committed value. Specifically, for commitments C = Commit1(y), D = Commit2(x), of value y and a tuple x = (x1, . . . , xL), respectively, our argument system allows one to demonstrate the knowledge of (x, y) such that x is a representation of y to bases h1, . . . , hL. That is, y = hx11 · · · hxLL . Our argument system is zero-k...

Pointcheval and Stern introduced in 1996 some forking lemmas useful to prove the security of a family of digital signature schemes. This family includes, for example, Schnorr's scheme and a modi cation of ElGamal signature scheme. In this work we generalize these forking lemmas to the ring signatures' scenario. In a ring signature scheme, a signer in a subset (or ring) of potential signers prod...

Ring signatures are an important primitive for protecting signers’ privacy while ensuring that a signature in question is indeed issued by some qualified user. This notion can be seen as a generalization of the well-known notion of group signatures. A group signature is a signature such that a verifier can establish its validity but not the identity of the actual signer, who can nevertheless be...

In this paper, we propose an efficient (n − t)-out-of-n threshold ring signature scheme which is efficient when t is small compared with n. Our scheme has a kind of dual structure of the Bresson– Stern–Szydlo threshold ring signature scheme [2], which is infeasible when t is small compared with n. In particular, we modify the trap-door one-way permutations in the ring signature scheme, and use ...