Multi-proxy Signature Schemes for Partial Delegation with Cheater Identification

The authors propose two multi-proxy signature schemes for partial delegation, in which the original signer can delegate his signing power to a set of proxy signers. One of the proposed schemes is designated on the proxyunprotected approach and the other is on the proxyprotected approach. Both proposed schemes satisfy the basic properties for partial delegation addressed by Mambo, Usuda, and Okamoto. The proxy-unprotected scheme is only applicable to the case that the original signer is honest, and however it is more efficient than the proxy-protected one. The proxy-protected scheme also has the ability to prevent attempts from cheating plotted by the original signer or by malicious proxy signer(s).