ably secure signature scheme with message recovery based on the elliptic-curve discrete logarithm. The proposed scheme is proven to be secure in the strongest sense (i.e., existentially unforgeable against adaptively chosen message attacks) in the random oracle model under the discrete logarithm assumption. We give a concrete analysis of the security reduction. When practical hash functions are...

In a proxy signature scheme, a user delegates his/her signing capability to another user in such a way that the latter can sign messages on behalf of the former. In this paper, we first propose a provably secure proxy signature scheme, which is based on a two-party Schnorr signature scheme. Then, we extend this basic scheme into designated-verifier proxy signatures (DVPS). More specifically, we...

The magic ink signature recently proposed in [11] is a blind signature which allows “unblinding” of a signature by authorities to establish what is known as audit trail and anonymity revocation in case of criminal activities. In [11] as well as in all the previous fair blind signature schemes (e. g., [2] and [10]), trustees need to search a database maintained by signers to obtain a transcript ...

Blind signatures are important techniques and are widely used in many e-commerce services, such as electronic voting and electronic cash system. In this article, we present a blind signature scheme based on elliptic curves cryptography and prove that it satisfies the requirements of blindness, unforgeability and untraceability.

Forward-secure signatures are proposed to tackle the key exposure problem, in which the security of all signatures prior to key leakage is still kept even if the secret key leaks. In this paper, we construct two forward-secure multisignature schemes, one forward-secure threshold signature scheme, and one forward-secure blind signature scheme. Our constructions are based on the recently proposed...

Network exchange is now widely used. However, it still cannot avoid the problems evolving from network exchange. For example. A buyer may not receive the order even if he/she makes the payment. For another example, the seller possibly get nothing even when the merchandise is sent. Some studies about the fair exchange have proposed protocols for the design of efficiency and exploited the signatu...

Chen, Qiu, and Zheng proposed a Rabin-like blind signature scheme, which is based on the square-root problem. Although their scheme is simple and efficient, it can be compromised when choosing some particular blinding factors. In this manuscript, the scheme is demonstrated as not being secure.

This paper studies non-committing type of universally composable (UC) blind signature protocols where an adversary does not necessarily commit to a message when requesting a signature. An ordinary UC blind signature functionality requires users to commit to the message to be blindly signed. It is thereby impossible to realise in the plain model. This paper first shows that even non-committing v...

Rapid development of data processing systems has made digital signatures an essential application. A digital signature basically associates a signer with the message. Its important characteristics are easy verification, unforgeability and undeniability. However, conventional digital signature schemes generally consider only single signer situations; this is impractical, because the authorized s...