标准模型下基于身份的混淆乐观公平交换方案

为防止签名验证者利用部分签名取得不公平的优势，Huang等人提出混淆乐观公平交换（Ambiguous Optimistic Fair Exchange，AOFE）方案及其一般构造方法，但是其构造方法没有考虑真实的用户环境.在基于IBC（Identity-Based Cryptography）的用户环境下，文章提出基于身份的混淆乐观公平交换（ID-AOFE）方案构造方法、方案实例、及其选择身份安全模型.提出的ID-AOFE构造方法对Huang等人的AOFE方案进行了简化，采用具有信息提取功能的证据不可区分证明算法替换原方案模型中的基于标签加解密和零知识证明算法.ID-AOFE安全模型以Huang等人的AOFE安全模型为基础，融合了选择身份安全模型，并对ID-AOFE方案的安全性进行了归纳和重新定义.在选择身份安全模型下，提出的ID-AOFE方案实例的公平性被规约到经典密码原语的安全性.此外，文章探讨了ID-AOFE方案的消息交互模型，就争端解决的方案和过程进行了重点分析.

ID-Based Ambiguous Optimistic Fair Exchange in the Standard Model

A generic ambiguous optimistic fair exchange(AOFE)scheme,a variant of OFE,is proposed by Huang et al.The AOFE scheme prevents signature verifiers from convincing anybody about the authorship of a partial signature generated by the signer.However,the AOFE scheme cannot be directly applied to an actual user environment.A generic AOFE scheme and an instantiation of the generic construction in an identity-based user environment were proposed in this paper.In the generic construction of identity-based AOFE(ID-AOFE),the tag-based encryption and zero-knowledge proof algorithms in Huang et al.'s AOFE was removed and the non-interactive witness indistinguishable proof algorithms extracting the hided witness via keys was employed.Furthermore,we summarized and redefined the security of the ID-AOFE scheme.Then,an ID-AOFE security model was defined based on the Huang et al.'s AOFE security model and the selective identity security model.Under the selective identity security model of ID-AOFE,the fairness of our scheme is reduced to the securities of several classical cryptographic primitives.In addition,this paper discussed the message interaction model of the ID-AOFE scheme,and analyzed the mechanism of dispute resolution.