Secure communication is considered with unreliable entanglement assistance, where the adversary may intercept the legitimate receiver's entanglement resource before communication takes place. The communication setting of unreliable assistance, without security aspects, was originally motivated by the extreme photon loss in practical communication systems. The operational principle is to adapt the transmission rate to the availability of entanglement assistance, without resorting to feedback and repetition. Here, we require secrecy as well. An achievable secrecy rate region is derived for general quantum wiretap channels, and a multi-letter secrecy capacity formula for the special class of degraded channels.

翻译：考虑在不可靠纠缠辅助下的安全通信问题，其中对手可能在通信发生前拦截合法接收方的纠缠资源。最初，无安全方面的不可靠辅助通信设置源于实际通信系统中极端的光子损耗。其运行原则是在不借助反馈和重传的情况下，根据纠缠辅助的可用性调整传输速率。在此我们进一步要求保密性。针对一般量子窃听信道推导了可达的保密速率区域，并为退化信道这一特殊类别给出了多字符保密容量公式。