In this paper we shall introduce a new electronic payment concept based on the popular direct debit payment model, entitled periodical payments. The direct debit model currently in use online is neither secure nor flexible, and requires a leap of faith by the customer who must trust the merchant to behave honestly. Electronic direct debit request (DDR) forms are not signed by both parties in a ...

Cao-Cao’s recently proposed an identity-based proxy signature scheme and claim that the scheme is provably secure in random oracle model. In this paper we have reviewed the scheme and proven that the scheme is vulnerable to chosen message attack under the defined security model. To prevent this attack, we propose an improved version of the scheme. A Proxy multi-signature scheme allows an author...

We propose a scalable Web document sharing infrastructure model called Browsers-Aware Proxy Server. In this design, a proxy server connecting to a group of networked clients maintains an index file of data objects of all clients’ browser caches. If a user request misses in its local browser cache and the proxy cache, the browsers-aware proxy server will search the index file attempting to find ...

We provide an enhanced security model for proxy signatures that captures a more realistic set of attacks than previous models of Boldyreva et al. and of Malkin et al.. Our model is motivated by concrete attacks on existing schemes in scenarios in which proxy signatures are likely to be used. We provide a generic construction for proxy signatures secure in our enhanced model using sequential agg...

Identity-based (ID-based) public key cryptosystem can be a good alternative for certificate-based public key setting, especially when efficient key management and moderate security are required. In a (t, n) threshold proxy signature scheme, the original signer delegates the power of signing messages to a designated proxy group of n members. Any t or more proxy signers of the group can cooperati...

The notions of identity-based multi-proxy signature, proxy multi-signature and multi-proxy multisignature have been proposed to facilitate public key certificate management of these kinds of signatures by merely employing signer’s identities in place of the public keys and their certificates. In the literature, most identitybased multi-proxy signature, proxy multi-signature and multi-proxy mult...

Transitive proxy voting (or ‘liquid democracy’) is a novel form of collective decision making, often framed as an attractive hybrid direct and representative democracy. Although the ideas behind liquid democracy have garnered widespread support, there been relatively few attempts to model it formally. This paper makes three main contributions. First, proposes new social choice-theoretic democra...

In a (t, n) designated verifier threshold proxy signature scheme, an original signer can delegate his/her signing power to n proxy signers such that any t or more out of n proxy signers can sign messages on behalf of the original signer but t− 1 or less of the proxy signers cannot generate a valid proxy signature. Of course, the signature is issued for a designated receiver and therefore only t...