Two-Party Adaptor Signature Scheme Based on IEEE P1363 Identity-Based Signature

Adaptor signature is extended from the standard digital signature, which conceals a secret value in the “pre-signature”. The one who knows the secret value can transform it into a completed signature. Adaptor signatures are useful in addressing blockchain scalability issues, and have been used to build blockchain scaling protocols, such as payment channels or atomic swaps. Recently, someone propose two-party adaptor signature to enhance the privacy in application of adaptor signatures. However, we notice that there is no identity-based two-party adaptor signature scheme so far. Based on IEEE P1363 standard identity-based signature scheme, a secure two-party adaptor signature is constructed in this paper. Moreover, under the random oracle model, we analyze the security of our proposed P1363-based two-party adaptor signature. Finally, we make a comparison between our scheme and other adaptor signature schemes in computation and communication overheads, the result shows the costs of our scheme are acceptable.