In recent years it has been trying that with regard to the question of computational complexity of discrete logarithm more strength and less in the elliptic curve than other hard issues, applications such as elliptic curve cryptography, a blind  digital signature method, other methods such as encryption replacement DLP. In this paper, a new blind digital signature scheme based on elliptic curve...

A proxy blind signature combines the properties of proxy signature and blind signature. Recently, Awasthi and Lal proposed a more efficient proxy blind signature based on the proxy signature scheme proposed by Mambo et al.. Later, Sun et al. and Das et al. gave some attacks on Awasthi and Lal’s scheme respectively. In this paper, we analyze the two attacks and we point out that those attacks do...

Directed signature is the solution of such problems when the signed message contains information sensitive to the signature receiver. Generally, in many application of directed signature, the signer is generally a single person. But when the message is on behalf of an organization, a valid sensitive message may require the approval of several people. Threshold signature schemes are used to solv...

Using Russian digital signature (DS) standards as the underlying scheme there are designed the blind DS protocols that are the first known implementation of the blind DS based on signature standards. There are also proposed blind collective DS protocols based on the DS standards. The last protocols are also the first implementation of the blind multi-signature schemes using the signature verifi...

A blind signature scheme is a 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. Blind signature schemes are used in anonymous digital payment systems. Since the existing proposals of blind signature schemes provide perfect unlinkability, such payment systems could be misused by criminals, e.g. t...

This paper presents two types of digital signature schemes combinely that are blind signature and proxy signature. In the proxy blind signature scheme, a signer other than the original signer signs the document as the agent of the original signer not knowing the meaning of the message. In this paper, an enhanced proxy blind signature is proposed, in which a time stamp approach is added to the p...

In a proxy signature scheme, a potential signer delegates his signing power to a proxy, who signs a message on behalf of the original signer. In a blind signature scheme, the signee cannot link the relationship between the blind message and the signature of the chosen message. That is, the signee cannot make a linkage between the blind signature and the identity of the requester. Therefore, it ...

Privacy homomorphisms, encryption schemes that are also homomorphisms relative to some binary operation, have been studied for some time, but one may also consider the analogous problem of homomorphic signature schemes. In this paper we introduce basic definitions of security for homomorphic signature systems, motivate the inquiry with example applications, and describe several schemes that are...

Blind signature is the concept to ensure anonymity of e-coins. Untracebility and unlinkability are two main properties of real coins, which require mimicking electronically. Whenever a user is permitted to spend an e-coin, he is in need to fulfill above requirements of blind signature. This paper proposes a proxy blind signature scheme with which a proxy is able to make proxy blind signature wh...

Using the digital signature (DS) scheme specified by Belarusian DS standard there are designed the collective and blind collective DS protocols. Signature formation is performed simultaneously by all of the assigned signers, therefore the proposed protocols can be used also as protocols for simultaneous signing a contract. The proposed blind collective DS protocol represents a particular implem...