The paper proposes four new ID based strong designated verifier proxy signature (SDVPS) scheme. The schemes are formed by introducing proxy in ID based SDVS, ID based in SDVPS and ID based proxy in SDVS. We have also analyzed the security of the schemes and their computation aspects.

To strengthen the anonymity of Bitcoin, several centralized coin-mixing providers (mixers) such as BitcoinFog.com, BitLaundry.com, and Blockchain.info assist users to mix Bitcoins through CoinJoin transactions with multiple inputs and multiple outputs to uncover the relationship between them. However, these mixers know the output address of each user, such that they cannot provide true anonymit...

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...

Elliptic Curve Cryptosystems (ECC) have recently received significant attention by researchers due to their high performance such as low computational cost and small key size. In this paper a novel untraceable blind signature scheme is presented. Since the security of proposed method is based on difficulty of solving discrete logarithm over an elliptic curve, performance of the proposed scheme ...

In this paper, we demonstrate that e-voting protocols based on threshold blind signatures from multiple authorities allow a coalition of eligible voters to cast more than votes. This property presents a serious violation of the principles of democracy in the voting process. We analyze the applicability of this violation and provide a generic solution using a public registration board and modifi...

Mu et al. proposed an electronic voting protocol and claimed that it protects voter’s anonymity, detects double voting and authenticates eligible voters. It has been shown that it does not protect voter’s privacy and prevent double voting. After that several improvement have been presented on it which suffer from the same weaknesses. One of the latest improvement on it, relates to Rodriguez-Hen...

In this work, we consider a scenario that includes an individual sharing his genomic data (or results obtained from his genomic data) with a service provider. In this scenario, (i) the service provider wants to make sure that received genomic data (or results) in fact belongs to the corresponding individual (and computed correctly), (ii) the individual wants to provide a digital consent along w...

Blind signature scheme, an important cryptographic primitive, is useful in protocols that guarantee the anonymity of the participants. Most of the developed blind signatures are based on a single hard problem. If one finds a solution to this problem then the blind scheme is breakable. In this paper, we presented a new blind signature scheme based on factoring and discrete logarithms. This kind ...

We show a new protocol for blind signatures in which security is preserved even under arbitrarily-many concurrent executions. The protocol can be based on standard cryptographic assumptions and is the first to be proven secure in a concurrent setting (under any assumptions) without random oracles or a trusted setup assumption such as a common reference string. Along the way, we also introduce n...