【摘要】 基于实际量子密钥分配系统中所使用的强衰减的激光脉冲不是单光子 ,量子密钥分配的信道不是无损耗的 ,光子计数器存在探测效率和暗计数以及窃听者的技术能力也不是无限的这些具体问题 .采用了分束与Breidbart基相结合的窃听策略讨论了窃听问题并给出了合法用户在筛选后的密钥中所能容忍的误码率上限公式 .更多还原

【Abstract】 Based on practical implementations of quantum cryptography with the attenuated l aser pulses as the signal source rather than single photon, as well as lossy cha nnels, detection efficiency, dark count of single-photon counter, and technolog ical possibilities of a realistic eavesdropping, we discuss a combining eavesdro pping strategy of Breidbart basis and beamsplitting, and give a bound on maximum disturbance for a given mean photon number and transmission length for which a secret key can be distilled.更多还原