A privacy-protecting proxy signature scheme and its application

Abstract

Proxy signatures are signature schemes that a signer (called original signer) delegates his signing capability to other people (called proxy signer), and the proxy signer creates signatures on behalf of the original signer. In application such as electronic voting and electronic commerce, the privacy may be concerned by the original signer. The original signer may hope that the proxy signers can sign on behalf of him without knowing the content of the signed message. Few efforts have been put on privacy protection of original signer in existed proxy signature schemes. In this paper, a privacy-protecting proxy signature scheme is proposed. In this scheme, the messages the original signer entrust to the proxy signer to sign on behalf of him are secret from the proxy signer during the generation of the proxy signature and from other people except the receiver designated by the original signer. Therefore, the privacy of the original signer is protected. The security of the proposed signature scheme is analyzed and its application to electronic voting is described.