Shiang-Feng Tzeng

A nonrepudiable threshold multi-proxy multi-signature scheme with shared verification

In this paper, we shall propose a threshold multi-proxy multi-signature scheme with shared verification. In the scheme allows the group of original signers to delegate the signing capability to the designated group of proxy signers. Furthermore, a subset of verifiers in the designated verifier group can authenticate the proxy signature. A threshold multi-proxy multisignature scheme with the nonrepudiation property is a scheme where the proxy group cannot deny signing for the message and the verifier group can identify the proxy group for a proxy signature.

Generalization of proxy signature based on elliptic curves

Abstract In the past, proxy signature schemes were usually proposed to deal with one or two separate proxy conditions each. To make a difference, in this paper, the authors shall present a generalized version of proxy signature scheme. Compared to earlier proxy signature schemes, our novel scheme can be applied to every possible proxy situation. The proposed scheme allows the original group of original signers to delegate their signing capability to a designated proxy group. The proxy group of proxy signers can cooperatively generate a proxy signature on behalf of the original group. Any verifier can verify the proxy signature on the message with the knowledge of the identities of the actual original signers and the actual proxy signers. With this article, we also aim to demonstrate how to specify proxy signature schemes on elliptic curve over finite fields. In addition, some possible attacks have also been considered, and our security analysis will show that none of them can successfully break the proposed scheme.

An improvement of nonrepudiable threshold proxy signature scheme with known signers

In a (t, n) threshold proxy signature scheme, which is a variant of the proxy signature scheme, the proxy signature key is shared among a group of n proxy signers delegated by the original signer. Any t or more proxy signers can cooperatively sign messages on behalf of the original signer. In 2000, Hwang et al. (Int J Inf 11 (2000) 1) proposed a secure nonrepudiable threshold proxy signature scheme with known signers. In this paper, we point out a cryptanalysis of their scheme. Furthermore, we improve the security of the threshold proxy signature scheme which remedies the weakness of Hwang et al.s scheme.

On the efficiency of nonrepudiable threshold proxy signature scheme with known signers

In the (t,n) proxy signature scheme, the signature signed by the original signer can be signed by t or more proxy signers out of a proxy group of n proxy signers. Recently, Hsu et al. proposed a nonrepudiable threshold proxy signature scheme with known signers. In this article, we shall propose an improvement of Hsu et al.s scheme that is more efficient in terms of computational complexity and communication cost.

Digital signature with message recovery and its variants based on elliptic curve discrete logarithm problem

Abstract In this article, we shall adopt the concepts of elliptic curve cryptosystems and self-certified public keys to build a novel digital signature scheme with message recovery. The public key and the identity of the user can be authenticated simultaneously in recovering the message. In addition, we shall also present three extended digital signature schemes based on the proposed scheme. The first is an authenticated encryption scheme that only allows a designated verifier to retrieve and verify the message. The second is an authenticated encryption scheme with message linkages used to deliver a large message. And the third is for message flows. The authenticated encryption scheme with message linkages for message flows allows the verifier to recover partial message blocks before obtaining the whole signature. Some possible attacks will be considered, and our security analysis will show that none of them can successfully break any of the proposed schemes.

A NEW CONVERTIBLE AUTHENTICATED ENCRYPTION SCHEME BASED ON THE ELGAMAL CRYPTOSYSTEM

A convertible authenticated encryption scheme allows a designated receiver to retrieve an authenticated ciphertext and convert the authenticated ciphertext into an ordinary signature. The receiver ...

Improvement of signature scheme based on factoring and discrete logarithms

Laih and Kuo proposed two efficient signature schemes based on discrete logarithms and factorization. However, their schemes require many keys for a signing document. In this article, we shall propose an improvement of Laih and Kuos signature schemes. The improved scheme will outperform their schemes in the number of keys.

A BATCH VERIFICATION FOR MULTIPLE PROXY SIGNATURE

In this article, we proposed a batch verification scheme for multiple proxy signatures to reduce the proxy signature verification time. The proposed scheme is not only efficient because it does not...

A new convertible authenticated encryption scheme with message linkages

In this article, we present an authenticated encryption scheme with message linkages used to deliver a large message. To protect the receivers benefit, the receiver can easily convert the signature into an ordinary one that can be verified by anyone. Several feasible attacks will be discussed, and the security analysis will prove that none of them can successfully break the proposed scheme.

A new digital signature scheme based on factoring and discrete logarithms

This article proposes a new digital signature scheme based on the difficulty of simultaneously factoring a composite number and computing discrete logarithms. In the proposed scheme, each user uses common arithmetic moduli and only owns one private key and one public key. Furthermore, some possible limitations have been analyzed, but none of them can successfully over-rule the proposed scheme.