In a multi-proxy multi-signature scheme, a group of original signers can delegate the signing rights to a group of proxy signers. All proxy signers cooperatively sign messages on behalf of the original group. Recently, Sahu and Padhye proposed an identity-based multi-proxy multi-signature (IBMPMS) scheme which was claimed to be secure against existential forgery on adaptive chosen-message and a...

In this paper, we investigate the recent paradigm for group signatures proposed by Rivest et al . at Asiacrypt ’01. We first improve on their ring signature paradigm by showing that it holds under a strictly weaker assumption, namely the random oracle model rather than the ideal cipher. Then we provide extensions to make ring signatures suitable in practical situations, such as threshold scheme...

In 2010, Resch and Plank proposed a computationally secure secret sharing scheme, called AONT-RS. We present a generalisation of their scheme and discuss two ways in which information is leaked if used to distribute small ciphertexts. We discuss how to prevent such leakage and provide a proof of computational privacy in the random oracle model. Next, we extend the scheme to be robust and prove ...

In this paper, we investigate the recent paradigm for group signatures proposed by Rivest et al.. at Asiacrypt ’01. We first improve on their ring signature paradigm by showing that it holds under a strictly weaker assumption, namely the random oracle model rather than the ideal cipher. Then we provide extensions to make ring signatures suitable in practical situations, such as threshold scheme...

In this paper, we introduce a new threshold signature RSA-typed scheme. The proposed scheme has the characteristics of un-forgeable and robustness in random oracle model. Also, signature generation and verification is entirely non-interactive. In addition, the length of the entity signature participate is restricted by a steady times of the length of the RSA signature modulus. Also, the signing...

In this paper, we investigate the recent paradigm for group signatures proposed by Rivest et al. at Asiacrypt '01. We rst improve on their ring signature paradigm by showing that it holds under a strictly weaker assumption, namely the random oracle model rather than the ideal cipher. Then we provide extensions to make ring signatures suitable in practical situations, such as threshold schemes o...

We consider a generalization of the standard oracle model in which the oracle acts on the target with a permutation which is selected according to internal random coins. We show new exponential quantum speedups which may be obtained over classical algorithms in this oracle model. Even stronger, we describe several problems which are impossible to solve classically but can be solved by a quantum...

Known practical blind signature schemes whose security against adaptive and parallel attacks can be proven in the random oracle model either need five data exchanges between the signer and the user or are limited to issue only logarithmically many signatures in terms of a security parameter. This paper presents an efficient blind signature scheme that allows a polynomial number of signatures to...

In this paper, we investigate the recent paradigm for group signatures proposed by Rivest et al . at Asiacrypt ’01. We first improve on their ring signature paradigm by showing that it holds under a strictly weaker assumption, namely the random oracle model rather than the ideal cipher. Then we provide extensions to make ring signatures suitable in practical situations, such as threshold scheme...

In this paper we present efficient implementations of McEliece variants using quasi-dyadic codes. We provide secure parameters for a classical McEliece encryption scheme based on quasi-dyadic generalized Srivastava codes, and successively convert our scheme to a CCA2-secure protocol in the random oracle model applying the Fujisaki-Okamoto transform. In contrast with all other CCA2-secure code-b...