Abstract: A group blind signature require that a group member signs on group’s behalf a document without knowing its content. In this paper we propose an efficient and secure group blind signature scheme. Our scheme is an extension of the group signature scheme proposed by Ateniese, Camenisch, Joye and Tsudik that adds the blindness property. We prove that our group blind signature scheme has t...

(Sequential) Aggregate signature schemes enable a group of users u1, . . . , uk with messages m1, . . . ,mk to produce a single signature Σ which states the integrity and authenticity of all the messages m1, . . . ,mk. The length of the signature Σ is thereby significantly shorter than a concatenation of individual signatures. Therefore, aggregate signatures can improve the efficiency of numero...

In this paper, we propose an Undeniable Blind Signature scheme (UBSS) based on isogenies between supersingular elliptic curves. The proposed UBSS is an extension of the Jao-Soukharev undeniable signature scheme [19]. We formalize the notion of a UBSS by giving the formal definition. We then study its properties along with the pros and cons. Based on this, we provide a couple of its applcations....

We introduce the notion of automorphic signatures, which satisfy the following properties: the verification keys lie in the message space, messages and signatures consist of group elements only, and verification is done by evaluating a set of pairing-product equations. These signatures make a perfect counterpart to the powerful proof system by Groth and Sahai (Eurocrypt 2008). We provide practi...

Verifiably encrypted signatures are used when Alice wants to sign a message for Bob but does not want Bob to possess her signature on the message until a later date. Such signatures are used in optimistic contact signing to provide fair exchange. Partially blind signature schemes are an extension of blind signature schemes that allows a signer to sign a partially blinded message that include pr...

This paper concerns blind signature schemes. We focus on two moves constructions, which imply concurrent security. There are known efficient blind signature schemes based on the random oracle model and on the common reference string model. However, constructing two move blind signatures in the standard model is a challenging task, as shown by the impossibility results of Fischlin et al. The rec...

Recently the bilinear pairing such as Weil pairing or Tate pairing on elliptic curves and hyperelliptic curves have been found various applications in cryptography. Several identity-based (simply ID-based) cryptosystems using bilinear pairings of elliptic curves or hyperelliptic curves were presented. Blind signature and ring signature are very useful to provide the user’s anonymity and the sig...

A proxy signature scheme enables a proxy signer to sign messages on behalf of the original signer. In this paper, we demonstrate that a number of discrete logarithm based proxy signature schemes are vulnerable to an original signer’s forgery attack. In this attack, a malicious original signer can impersonate a proxy signer and produce a forged proxy signature on a message. A third party will in...

In the universal composability framework, we define an ideal functionality for blind signatures, as an alternative to a functionality recently proposed by Fischlin. Fischlin proves that his functionality cannot be realized in the plain model, but this result does not apply to our functionality. We show that our functionality is realized in the plain model by a blind signature protocol if and on...

Aggregate signature scheme proposed by Boneh, Gentry, Lynn, and Shacham allows n signatures on n distinct messages from n distinct users to aggregate a single signature that convince any verifier that n users did indeed sign the n messages, respectively. The main benefit of such schemes is that they allow bandwidth and computational savings. In this paper, we question about whether the existing...