If you turn the envelope upside down, the key will fall out.

你如果把信封倒过来，钥匙就会掉出。

《新英汉大辞典》

Based on the object to be called and the arguments found in the SOAP envelope, as seen in Listing 1, you can generate such a key.

在将被调用的对象和SOAP信封中的变元的基础上(如清单1所示)，您可以生成这样一个密钥。

youdao

One of the key advantages of DSig-based protocols is the ability to both assert identity and create a tamper-proof envelope of the content of the message which are often both required together.

基于DSig的协议有个很主要的优势——断定身份的同时还能创建消息内容的防篡改信封，这两个功能通常都要求同时出现。

youdao

However, it has limited control over the taxation system, the overall spending envelope and key spending decisions such as welfare.

BBC: Scotland politics