The security analysis of quantum SAGR04 protocol in collective-rotation noise channel

Noise exists in the actual communication environment. It is necessary and significant to analyze the security of SAGR04 protocol in the noise environment. An excellent model of collective rotation noise analysis is introduced and the discussing of the security of SAGR04 protocol is based on the method of information theory. The eavesdropping can be detected for the increment of the qubit error rate and eavesdropper can maximally get about 50% of the keys. It can be concluded that the SAGR04 protocol, used as quantum key distribution, is secure.