Blind signatures, introduced by Chaum, allow a user to obtain a signature on a message without revealing any thing about the message to the signer. Blind signatures play an important role in plenty of applications such as e-voting, e-cash system where anonymity is of great concern. Identity based(ID-based) public key cryptography can be a good alternative for certificate based public key settin...

Cryptography is increasingly applied to the E-commerce world, especially to the untraceable payment system and the electronic voting system. Protocols for these systems strongly require the anonymous digital signature property, and thus a blind signature strategy is the answer to it. Chaum stated that every blind signature protocol should hold two fundamental properties, blindness and intractab...

We explicitly describe and analyse blind hierachical identity-based encryption (blind HIBE) schemes, which are natural generalizations of blind IBE schemes [20]. We then uses the blind HIBE schemes to construct: (1) An identity-based blind signature scheme secure in the standard model, under the computational Diffie-Hellman (CDH) assumption, and with much shorter signature size and lesser commu...

The threshold proxy signature scheme allows the original signer to delegate a signature authority to the proxy group to cooperatively sign message on behalf of an original signer. In this paper, we propose a new scheme which includes the features and benefits of the RSA scheme. Also, we will evaluate the security of undeniable threshold proxy signature scheme with known signers. We find that th...

In this paper, we proposed a scheme to implement ‘Electronic Voting’ an important application of Blind digital Signature using elliptic curve cryptographic algorithm. The selection of this algorithm is its difficulty in solving it. The algorithm is used in combination with the blinding factor to scramble the contents of the message to be signed by the signer so that the signer do not come to kn...

In a nominative proxy signature scheme, an original singer delegates his signing power to a proxy signer, who generates a nominative signature on behalf of the original signer. In a nominative proxy signature scheme, only the nominee can verify the signature and if necessary, only the nominee can prove its validity to the third party. In this paper, we first classify the nominative proxy signat...

In the past few years, many excellent studies on proxy signature schemes have been published. Yet, traditional proxy signature schemes are mainly aimed at dealing with one or two separate proxy conditions each. In this article, the authors shall present a generalized version of the (t1/n1 – t2/n2) proxy signature scheme based on the discrete logarithms that can be applied to every proxy situati...

In a nominative proxy signature scheme, an original singer delegates his signing power to a proxy, who generates a nominative signature on behalf of the original signer. In a nominative proxy signature scheme, only the nominee can verify the signature and if necessary, only the nominee can prove its validity to the third party. In this paper, we first classify the nominative proxy signature int...

In this paper we propose an anonymous mobile payment system based on a group blind signature scheme in order to prevent blackmailing. The message transfer from the customer to the merchant occurs only once during the payment protocol. Also, the amount of communication between customer and merchant is about 900 Bytes. Therefore, our mobile payment system can be used in the wireless networks with...

A blind signature scheme is a cryptographic protocol for obtaining a signature from a signer such that the signer’s view of the protocol cannot be linked to the resulting message signature pair. In this paper we have proposed two blind signature schemes using braid groups. The security of given schemes depends upon conjugacy search problem in Braid groups.