An Efficient Strong Designated Verifier Signature Scheme

This paper proposes a designated verifier signature scheme based on the Schnorr signature and the Zheng signcryption schemes. One of the advantages of the new scheme compared with all previously proposed schemes is that it achieves the “strong designated verifier” property without encrypting any part of the signatures. This is because the designated verifier’s secret key is involved in the verification phase. Another advantage of the proposed scheme is the low communication and computational cost. Generating a signature requires only one modular exponentiation, while this amount is two for the verification. Also, a signature in our scheme is more than four times shorter than those of known designated verifier schemes.