Abstract: Aiming at the disadvantages of existed fair contract signing protocol based on short signature scheme without random oracles and q-strong Diffie-Hellman assumption, a new fair contract signing protocol with the off-line semi-Trusted Third Party(TTP) is proposed. The off-line semi-TTP intervenes into the protocol to assist to decrypt in case of trouble, at the end of the protocol run, the TTP does not obtain signatures from the participating party. Because this protocol is based on short signature, which needs low storage and little communication, it can be used in low-bandwidth communication and low-storage environments.

Key words: bilinear pairings, short signature, q-strong Diffie-Hellman assumption, fair contract signing protocol

摘要： 针对目前已有的公平合同签署协议存在的不足，利用已有的无随机预言机模型下的短签名方案和q-强Diffie- Hellman假设，设计一种新的具有离线半可信第三方的公平合同签署协议，离线第三方只在意外情况下才介入协议，且在纠纷解决阶段只是协助参与方解密，则协议结束，第三方并不能获得参与方的签名。由于基于短签名，所需存储和通信的数据量小，该协议只适用于低带宽通信以及需要较小的数据存储量的环境。

关键词: 双线性对, 短签名, q-强Diffie-Hellman假设, 公平合同签署协议

CLC Number: 

• TP18