Confidentiality is somewhat tricky in the asynchronous scenario, because the PKI techniques used in a one-to-one interaction between a client and service provider can't be applied.
保密性在异步场景中有些麻烦，因为不能应用pki技术中使用的客户端和服务提供者之间的一对一交互。
It is a tricky issue for Apple because what Spotify plans to offer iPhone users - an unlimited on-demand music service - competes with Apple's own iTunes.
对苹果而言这可是一个棘手的问题，因为Spotify计划提供给iPhone用户一个无限制的音乐点播服务，这将会同苹果自己的iTunes形成竞争。
Dividing a service into input and output services can be tricky.
将服务分割成输入与输出服务可能很棘手。
Dividing a service into input and output services can be tricky.
将服务分割成输入与输出服务可能很棘手。
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