Investigation of non-repudiation protocols

Abstract

The paper surveys the state of non-repudiation protocols. A fair non-repudiation protocol should provide an equal protection to the sender and the recipient. A number of current non-repudiation protocols expect the protection from or partly from a Trusted Third Party (TTP). In practice, the sender and the recipient that do not trust each other, do not expect or are not able to find an TTP or a strong TTP in some circumstances. A simultaneous secret exchange protocol seems to be one of efficient solutions without an TTP to prevent entities from denying the transferring (sending or receiving) of certain messages. The secret exchange bit by bit, however, is neither very efficient nor convenient to the sender and the recipient in some cases. We introduce a model and a fair non-repudiation protocol without an TTP. In the protocol, the transferring of the message is split into three parts, a commitment C, a key K and an address for the key. Therefore, without bit by bit exchange, the protocol is more efficient than the existing non-repudiation protocols.