Simple Threshold RSA Signature Scheme Based on Simple Secret Sharing

Abstract

A new threshold RSA signature scheme is presented, which is based on a newly proposed simple secret sharing algorithm. The private key of RSA algorithm is divided into N pieces, and each piece is delivered to different participant. In order to digitally sign a message, each participant should calculate the partial signature for the message by using its own piece of shadow. Any K or greater than K participants out of N can combine the partial signatures to form a complete signature for the message. At the phase of signature combination, each participant’s partial secret (shadow) is not necessary to expose to others and the RSA private key is not required to reconstruct, thus the secret of the private key will not be exposed. Besides, fast computation and simple operation are also the features of this scheme.