In current proxy signature schemes, an original signer delegates her/his 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
are in general defective in proxy revocations. In this paper, we propose a proxy signature
scheme which allows the original signer to revoke delegations whenever necessary.
2004 Published by Elsevier Inc.
