Continuous variable quantum signature algorithm

A true quantum signature algorithm based on continuous-variable entanglement state is proposed. In the suggested algorithm, a key-pair, i.e. private signature key and public verification key, is generated based on a one-way function. By employing the signature key, a message state is encoded into a 2k-particle entangled state and a two-particle entangled state is prepared. The resulting states are exploited as a signature of the message state. The signature can be decoded under the verification key when it needs to be verified. Subsequently, a decoded message state and a two-particle entangled state are obtained. To compare the decoded states and the original states, a quantum circuit for comparing these states is exploited. Making use of measurement results of the quantum circuit one can judge the authenticity of the received signature. According to the security requirement of the signature scheme, the suggested algorithm has been proven to be theoretically secure by using the Shannon information theory.