SSL Settings

This section describes how to set your SSL preferences.

Privacy & Security Preferences - SSL

This section describes how to use the SSL preferences panel. If you are not already viewing the panel, follow these steps:

1. Open the &brandShortName; Edit menu and choose Preferences.
2. Under the Privacy & Security category, click SSL. (If no subcategories are visible, double-click Privacy & Security to expand the list.)

SSL Protocol Versions

The Secure Sockets Layer (SSL) protocol defines rules governing mutual authentication between a website and browser software and the encryption of information that flows between them. It is also used for secure communication in various other protocols, e.g., for protection of sensitive information exchanged with email, calendar, or directory servers. The newer Transport Layer Security (TLS) protocol is an IETF standard based on SSL but with its own version numbering. TLS 1.0 can be thought of as SSL 3.1, TLS 1.1 is in turn an update to TLS 1.0, etc. Newer protocols are preferred over older ones as they provide better security and more features. Older protocols are supported to ensure compatibility.

By default, &brandShortName; will select the most secure version which is widely supported to connect to the server. If that attempt doesn't succeed, it will try to connect with the next older version, etc., to the extent allowed by the settings in this panel. The connection will fail if no protocol supported by both sides is found. You can exclude older versions explicitly or allow newer versions which may not be widely supported yet with the following options:

• Enable: Check the SSL 3.0, TLS 1.0, TLS 1.1, and/or TLS 1.2 boxes to indicate which protocol versions can be used for a secure connection to a server.

Notes:

• At least one protocol version must be selected, thus it is not possible to uncheck the last remaining box.
• Also, the selection must be contiguous. It is not possible to select both SSL 3.0 and TLS 1.1 but to exclude the intermediate TLS 1.0 version.
• You can extend the range by multiple versions. For example, if only SSL 3.0 is currently checked and you select TLS 1.2, the TLS 1.0 and TLS 1.1 versions are automatically selected as well.
• Checkboxes may appear checked but grayed out if you cannot uncheck them without violating these rules. Uncheck the outermost boxes to regain access to an enclosed intermediate version.

SSL Warnings

It's easy to tell when the website you are viewing is using an encrypted connection. If the connection is encrypted, the lock icon in the lower-right corner of the browser window is locked. If the connection is not encrypted, the lock icon is unlocked.

If you want additional warnings, you can select one or more of the warning checkboxes in the SSL preferences panel. Some people find these warnings annoying.

To activate any of these warnings, select the corresponding checkbox:

• Loading a page that supports encryption: Select this warning if you want to be reminded whenever you are loading a page that supports encryption.
• Leaving a page that supports encryption: Select this warning if you want to be reminded whenever you are leaving a page that supports encryption for one that does not.
• Sending form data from an unencrypted page to an unencrypted page: Select this warning if you want to be reminded whenever you are submitting data over an unencrypted connection. If you send unencrypted information over the Internet, it can easily be intercepted by other people.
• Viewing a page with an encrypted/unencrypted mix: Select this warning if you want to be alerted whenever you are viewing a page that includes any information that's not encrypted.

For short definitions, click authentication, encryption, or certificate.

For more information about ciphers and encryption, see the following online documents:

• Introduction to Public-Key Cryptography
• Introduction to SSL
• Encryption Technologies Available in NSS 3.11.