An Anonymous but Accountable Proxy Multi-signature Scheme

in a proxy multi-signature, the proxy signer can sign a message on behalf of more than one original signer. However, in some cases, the proxy or the original signers do not want to leak the proxy signer's identity. In addition, when something is wrong with the signed message, the identity of the proxy signer has to be revealed. So the problem of anonymous but accountable has been proposed. Using the technology of pseudonym and secret sharing, in this paper, a simple method was proposed to reach the target of anonymous but accountable. In the scheme, the identity of the proxy signer was anonymous, but when t or more original signers want to reveal the proxy signer's identity, the proxy signer’s identity would be revealed and be demonstrated.