Proven secure blind adaptor signature scheme based on the SM2

Abstract

Adaptor signature (AS) is a novel cryptographic primitive that has gained prominence in recent years for its ability to link the signature process with the revelation of a secret value. The process involves adapting a pre-signature to a formal signature, ensuring that the final signature result aligns with conventional signatures. Both the pre-signature and the formal signature are capable of extracting a secret value, which endows AS with atomicity and suggests its promising application within blockchain technologies. However, the lack of anonymity in AS can lead to the exposure of transaction participants' identities, which may limit its application in scenarios demanding high privacy standards, such as electronic payments. To address this issue, a new blind adaptor signature system model and security model were proposed. Subsequently, a blind adaptor signature scheme was developed based on the SM2 signature algorithm, leveraging the new system model. The security of this new scheme, which was founded on the unforgeability and the hardness of the SM2 signature scheme, was demonstrated to meet the requirements of the newly proposed security model. Specifically, the scheme was proven to satisfy properties such as blindness, pre-signature adaptability, unforgeability, and witness extractability. Performance analysis indicates that the computational overhead of the SM2 blind adaptor signature scheme is minimal, with the total operation time of the signature process only increasing by a negligible 5.91ms compared to the SM2 adaptor signature scheme. Moreover, when compared to existing similar schemes, the SM2 blind adaptor signature scheme offers enhanced blindness and autonomy, making it particularly valuable for key application scenarios that necessitate high privacy requirements and the utilization of domestic cryptographic algorithms.

Keywords

• sm2 digital signature
• blind adaptor signature
• atomicity
• anonymity