We introduce signatures where signers can only sign messages that conform to some policy, yet privacy of the policy is maintained. We provide definitions and show that policy-based signatures provide a framework which yields a unified view of many other existing types of signatures that now appear as special cases. We also show how still other primitives are easily realized using policy-based signatures as a building block. We provide generic constructions of policy-based signatures and then show how to achieve them efficiently.
Policy-based signature, introduced by Bellare et al. REF , allows a signer to only sign messages conforming to some authority-specified policy.
Policy-Based Signatures
Public Key Cryptography
Computer Science