Digitally Sign Emails - Mozilla Thunderbird

Feb 21, 2024

Digitally Sign Emails - Mozilla Thunderbird

  1. Open a new email window in Mozilla Thunderbird. Go to Tools > Account Settings.

    New Email Window
  2. Click the Security tab. Click Select next to the Digital Signing field.

    Security Tab
  3. Choose the certificate you intend to use for signing. Click OK.

    Select the Certificate
    Note: If no certificates are present, it still needs to be imported. Follow these instructions and then return to this article to continue.
  4. You can choose the encryption certificate here as well:

    Choose Encryption Certificate
  5. To sign all messages, check Digitally sign messages (by default) under the Digital Signing field:
    Digitally Sign Messages
  6. Click OK to complete. 

    If you are not signing by default, proceed to the next step for instructions on signing a single email.
  7. When composing a new email in Thunderbird, click the Security drop down menu and choose Digitally Sign This Message.
    New Email Signing
    Note: To send encrypted messages, you must first receive a digitally signed email message from the recipient.

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