A new proxy signature scheme for a specified group of verifiers

In this article, we shall propose a ((t1, n1), (t2, n2)) proxy signature scheme with (t3, n3) shared verification based on the RSA problem. In this scheme, any t1 original signers can delegate the signing capability to the proxy group. After that, any t2 proxy signers can sign a message on behalf of the original group for a specified verifier group. Only any t3 verifiers together can check the validity of the proxy signature from the proxy group. The proposed scheme satisfies all proxy requirements of proxy signatures. Furthermore, the actual original signers and proxy signers can be individually identified in our scheme.