Policy-controlled signatures
Pairat Thorncharoensri, Willy Susilo, Yi Mu · Research Online (University of Wollongong) · 2009
In this paper, we present a new cryptographic primitive called “policy-controlled signature”. In this primitive, a signer can sign a message and attach some policies to it. Only a verifier who satisfies the policies attached can verify the authenticity of the message. This type of signature schemes has many applications, in particular to deal with sensitive data, where the signer does not want to allow anyone who is not authorized to verify its authenticity. Nonetheless, there is no existing cryptographic primitives that can offer this feature in the literature. Policy-controlled signatures can be seen to be similar to the notion of designated verifier signatures, as it can also be used to designate a signature to multiple recipients. When there is only a single attribute involved in a policy presented by a verifier, then we will achieve a designated verifier signature (with some trivial modifications). Therefore, policy-controlled signatures can be viewed as the generalization of the notion of the designated verifier signatures. We present a formal model to capture this notion. Furthermore, we also present a concrete scheme that is secure in our model. Finally, we briefly mention about an implementation that incorporates P3P to realize policy-controlled signatures.