Quantum message signature scheme without an arbitrator

A quantum message signature scheme based on quantum teleportation is presented In this scheme, Alice prepares N-pair particles m and m' in the same states which carry the quantum information while Bob generates N-pair particles a and b in EPR states, to each triplet composed of particles ai,bi and mi, Alice performs Bell-state measurement on mi and ai, to get signature, Bob compares the state of m'i and bi can verify the signature. This scheme does not rely on an arbitrator to verify the signature; however it has unconditional security and provides a higher efficiency in transmission.