Multiple grade proxy signature scheme based on key-insulated scheme CHENG Hua’qin, GAO Feng’xiu, MA Chuan’gui (Institute of Information Engineering, Information Engineering University, Zhengzhou, 450002) Abstract: Through analyzing the relation between key-insulated scheme and multiple grade proxy signature scheme, we find there are some identities and construct a new multiple grade signature scheme based on key-insulated scheme. In this scheme, a proxy signer can delegate his signing capabilities to a new proxy signer who could generate the signature on behalf of the original signer. Key words: key-insulated; proxy-signature; multiple-grade-proxy