Efficient Controlled Signature for a Large Network with Multi Security-level Setting
We present an efficient multi-level controlled signature. This primitive allows a signer to specify a security level to limit the accessibility of the signature and the message. The primitive works as follows. Let the security levels of a group of users defined in the ascending order, where “1” stands for the lowest security level and “10” represents the highest protection level, respectively. A signer signs on a message by setting a security layer “3”, which it is indicated that all users who were authorized with a level of security greater than “3” can verify this signature while cannot verify it. Many existing primitives, such as designated verifier signature, hierarchical identity-based signatures, policy-based signature, and attribute-based signature, are shared similarities with this primitive. However, our construction for this primitive is unique, concise and efficient compared to those existing primitives.