Multi-Designated Verifiers Signatures Revisited

Multi-Designated Verifier Signatures (MDVS) are privacy-oriented signatures that can only be verified by a set of users specified by the signer. We propose two new generic constructions of MDVS from variants of existing cryptographic schemes, which are ring signature from anonymous subset and multi-chameleon hash. We first devise a single add-on protocol which enables many existing identity-based (ID-based) ring signature schemes to support anonymous subset, which gives us three ID-based MDVS schemes. We then construct a multi-chameleon hash from an existing scheme with key exposure freeness. Interestingly, these two techniques can be seen as a multisignature version of Hess’s ID-based signature and Schnorr signature respectively.