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.