A Proxy Multi-Signature Scheme with Forward-Secure

The proxy multi-signature scheme allow a proxy signer to represent a group of users to sign a document. Like most of digital signature schemes, its security wholly depends on the security of secret keys. Once secret keys are exposed, all preciously assigned signatures must be reissued. Forward-secure signatures are used to address this problem, in which all previously generated signatures are still considered to be valid even after secret keys are compromised. In this paper, by borrowing the idea of hierarchical ID-based signature (HIBS), we integrated forward security into the proxy multi-signature scheme and proposed a proxy multi-signature scheme with forward-secure which supports the efficient batch verification of several signatures of the same message under different public keys. The security of our scheme relies on the hardness of computational Diffie-Hellman problem(CDHP) and Hash function.