Miyaji Laboratory

Abstract

Research on cryptographic primitives with low output locality is important for efficient protocol construction. The commitment method is an example of a cryptographic primitive. The commitment method is a protocol in which information is shared between the sender and the receiver, and the sender can determine the timing at which the receiver decrypts. The commitment method needs to be able to calculate efficiently while satisfying the security called binding and confidentiality. However, the commitment method with low output locality is not constructed. In this research, we first constructed two commitment schemes with low output locality. The first commitment method has the feature that the output locality is smaller than the input bit length (low output locality). The second commitment method is characterized in that the output locality is constant (constant output locality). Furthermore, we prove that each of the proposed commitment methods satisfies the binding and confidentiality.