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...

A new identity based proxy signature scheme Bin Wang Information Engineering College of Yangzhou University Yangzhou City, Jiangsu Province, P.R.China Tel: 086-0514-82220820 E-mail:[email protected] Abstract: Proxy signature schemes allow a proxy signer to generate proxy signatures on behalf of an original signer. Mambo et al. first introduced the notion of proxy signature and a lot of researc...

Digital signature scheme is an important research topic in cryptography. An ordinary digital signature scheme allows a signer to create signatures of documents and the generated signatures can be verified by any person. A proxy signature scheme, a variation of ordinary digital signature scheme, enables a proxy signer to sign messages on behalf of the original signer. To be used in different app...

A rich set of proxy signature schemes have been widely researched and discussed so far. However, they have been mainly focusing on dealing with one or two separate proxy situations each. In this article, the authors proposed the generalization of the (t1/n1 − t2/n2) proxy signature scheme based on the factorization of the square root modulo of a composite number. This scheme can be applied to e...

The method of indirect least squares (ILS) using a proxy for a discrete instrument is shown to identify a weighted average of local treatment e¤ects. The weights are nonnegative if and only if the proxy is intensity preserving for the instrument. A similar result holds for instrumental variables (IV) methods such as two stage least squares. Thus, one should carefully interpret estimates for cau...

In a (t, n) threshold proxy signature scheme, an original signer can delegate the signature authority to a proxy group of n member such that t or more than t proxy signers can cooperatively sign messages on behalf of the original signer, but t − 1 or fewer proxy signers cannot generate a valid proxy signature. In this paper, we review the security of C. L. Hsu et al.’s threshold proxy signature...

A proxy signature scheme allows an entity to delegate its signing power to another entity. Since the notion of proxy signatures was first introduced, many proxy signature schemes and various extensions have been considered. As an example, the notion of threshold proxy signature or proxy multi-signature was introduced as a group-oriented variant. In this paper, we show that some threshold proxy ...

In 2001, Hsu et al. proposed a non-repudiable threshold proxy signature with known signers. In their scheme, the proxy group cannot deny having signed the proxy signature if they did. However, Hsu et al.’s scheme is vulnerable to some attacks. A malicious original signer or malicious proxy signer can impersonate some other proxy signers to generate proxy signatures. In this article, we shall pr...

Proxy signature is a signature that an original signer delegates his or her signing capability to a proxy signer, and then the proxy signer creates a signature on behalf of the original signer. However, Sun et al. [7] showed that the proxy and multi-proxy signatures of Lee et al. [3], and the strong proxy signature scheme with proxy signer privacy protection of Shum et al. [6] are not against t...