The Security Preferences form You can use the Security Preferences form to configure access domains for web form configuration. Choose SSL version 3. Although the form presents SSL version 2 as an option, there are no IMAP clients that communicate over SSL with that version. Choose the ciphers you want your server to use. A cipher is the algorithm used in encryption.
Some ciphers are more secure, or stronger, than others.
Generally speaking, the more bits a cipher uses during encryption, the harder it is to decrypt the data. Ciphers are described after this list. Make sure you restart your server. When a browser initiates an SSL connection with the Messaging Server, it lets the server know what ciphers it prefers to use to encrypt information. In any two-way encryption process, both parties must use the same ciphers.