New Proxy Signature, Proxy Blind Signature and Blind Proxy Signature Based on Okamoto Signature

摘要

Proxy signature helps the proxy signer to sign messages on behalf of the original signer. In this paper, we propose a new protected proxy signature scheme. In the proposed scheme, the proxy signer can sign messages on behalf of the original signer with public key in the form of y = 9_1~(x_1)9_2~(x_2) by means of Okamoto signature scheme. Then, we extend our scheme to a new proxy blind signature and a new blind proxy signature by use of Okamoto-Schnorr blind signature. In our blind proxy signature scheme when one of the proxy signers sign message for the verifier, the original signer does not know which one belongs to the proxy signers, therefore, this scheme is suitable for many applications where the proxy signer's privacy is required.