A Time-stamping Proxy Signature Scheme Using Time-stamping Service

In current proxy signature schemes, an original signer delegates her signing capability to a proxy signer, and then the proxy signer can sign messages on behalf of the original signer. Although these schemes have succeeded in proxy delegations, they share a common problem. That is, a verifier cannot ascertain that a proxy signature was signed by the proxy signer during the valid delegation period. Additionally, these schemes do not support revocations. In this paper, we proposed a new time-stamping proxy signature scheme using time-stamping service to resolve the above problems. The security and performance of the proposed scheme are also analyzed.