Lotus Encryption (续一)

准备CLP-711考试时遇到这样两个题目：
1. Andre is using mail encryption on documents that are being routed to other members of his team. Which one of the following keys is used to decrypt the document?

Answer: D. Recipient's private key

2. Lucy is using mail encryption on documents that are being routed to other users on her team. Which one of the following keys is used to encrypt the documents?

Answer: C. Recipient's public key
通过以上两个题目引申出来一个问题：Lotus mail是如何进行encrypt和decrypt的，经过查阅Notes Administrator自带的Help，总结如下(其实Help描述的很详细，我也就是翻译一下而已)：
Lotus mail encryption分为两类：Notes mail encryption和S/MIME mail encryption针对两道问题下面只讨论Notes mail encryption(其实S/MIME mail encryption我也还没搞太清楚)。那Notes mail encryption是怎样工作的呢？
1. 邮件发件人在发送邮件时选择"Encrypt";
2. Notes会自动寻找recipient's public key(一般这个key是存放在Domino Directory上的，也就是names.nsf)，如果找不到recipient's public key那么加密就失败了，如果recipient是多人，能找到public key的就会加密成功，找不到的失败。
3. 收件人打开邮件时，系统会用收件人的private key去decrypt这个mail。