A trusted third party introduced in watermarking protocols would decrease the security and affect the implementation of the protocols. In this paper, a new watermarking protocol with an un-trusted third party （UTTP） was proposed. Based on the idea of all-or-nothing disclosure of secret （ANDOS）, all of the buyer, the seller and the third party didn＇t know the exact watermark, which was embedded in a digital content for tracing piracy. The proposed protocol provided mechanisms to trace piracy and protect customer＇s right. In addition, the problem that a seller colluded with UTTP to frame the buyer, namely, the conspiracy problem, could be avoided.
This paper presents a simple partially blind signature scheme with low computation. By converse using the partially blind signature scheme, we build a simple fair e-payment protocol. In the protocol, two participants achieve the goals of exchanging their digital signatures from each other in a simple way. An ado vantage of this scheme is that this approach does not require the intervention of the third party in any case. The low-computation property makes our scheme very attractive for mobile client and smart-card implementation in many e-commerce applications.
Treachery is one of the restrictions to the development of electronic commerce. To prevent the treachery from the participants in electronic commerce, in this paper a secure electronic payment scheme is proposed and its security is analyzed. This scheme can prevent the treachery only with the aid of an un-trusted third party. It is very simple and it also improves the security and provides the non-repudiation, accountability, fairness and privacy.
