Privacy and Security
Flex Confirm Mail Requires Restart
Confirm mail address and attachments based on flexible rules.
Confirm-Address Requires Restart
Confirm E-mail address before sending mail
Paranoia Requires Restart
Check if your emails arrived TLS-encrypted (and which corporations were able to read it nevertheless)
DKIM Verifier Requires Restart
Verifies the DKIM-Signature of an e-mail.
Check and Send Requires Restart
Check the message contents and addresses before you send the message...
Allow HTML Temp Requires Restart
This Add-on allows to have HTML temporarily allowed in the currently displayed message by only one click. When switching to another message, it'll be shown automatically again in plain text or simple html mode (if this is your default mode).
Encrypt if possible Requires Restart
Sets message security option "encrypt message", if valid X509 certificates are found for all recipients.
Signal Spam Requires Restart
Add simple functions to report spams or phishing to Signal Spam by one click.
The add-on will also alert you if you open a fraudulent e-mail (phishing).
Identity Chooser Requires Restart
Identity Chooser helps you to always use the correct identity when composing a new email.
Auto Address Cleaner Requires Restart
Removes comment, display name automatically from addresses before sending mail.
Key Manager Requires Restart
KeyManager Tool: Firefox Add-on for Key Generation, Certificate Enrollment, CRL Signing, and Identity and Authority Delegation
Identity Select Requires Restart
This extension allows you to choose the identity of your new email from a popup menu directly from the Write button. This feature behaves in a similar manner as the Get Mail pulldown menu. In addition, the default behavior of the Write button is...
GNOME keyring password integration Requires Restart
Extension that allows Firefox and Thunderbird to store passwords in Keyring, Gnome's default password store.
Soapy Requires Restart
Bypasses DNS-based censorship
NOTE: This was created as a SOPA protest in 2012. This does not work anymore for most sites. Use Tor instead.
Stego Block Requires Restart
Embeds a small secondary, encrypted message in an email, known as a Stego Block.
MDN Extended Requires Restart
Allows the recipient of a message to send a return receipt (MDN: Message Disposition Notification) on message deletion. This addon is usefull for better experience with Notification Viewer addon.
Disable About Something Requires Restart
Provides ability to disable "about:*" pages by the configuration.
Correct Identity Requires Restart
Ever sent mail from the wrong email address because you forgot to select the correct identity?
Security Settings from Address Book Requires Restart
Sets message security (sign/encrypt) when sending or saving messages based on recipients' address book entry's field "Custom1".
Minimum and fast URL blocker.