I administer several computers that have Thunderbird installed. I know Thunderbird has an option to require all email to be encrypted. However, I would like a way to allow unencrypted email normally, but require encrypted email to certain contacts.

For example, if I email ceo@mycompany.com, Thunderbird should require encryption, but if I email JohnDoe@othercompany.com Thunderbird would allow unencrypted emails.

Are there any settings or Add-ons that would give this functionality?


  • Major +1. Since Thunderbird dropped Enigmail this has been a major pain point and I don't know of any workaround. I have been leaking unencrypted traffic over the Internet because my muscle memory always remembers to turn off the encryption, even with emails that should be encrypted.
    – D-FENS
    Jan 24 at 10:10

3 Answers 3


I use open-pgp on thunderbird. Theres a setting in there for per recipient rules. I think thats what you're after?

  • That sounds like it might work. I will take a look.
    – Daniel
    Aug 24, 2012 at 22:35
  • The OP seems to be asking about S/MIME encryption, not PGP/GPG.
    – MV.
    Aug 27, 2012 at 23:57
  • I would still like a way to do this with S/MIME, however, your solution does solve my problem, so I will accept it.
    – Daniel
    Aug 31, 2012 at 13:06

As per 24. January 2022 there is no way to do that with Thunderbird (v.91.5.0).

There was when using the Enigmail extension, but as of TB version 78 this option is gone with the wind. This is a severe regression as compared to Enigmail, and a persistent one at that: 13 major versions of TB and no fix in sight.

Here is the relevant bit in the Thunderbird Q&A:


As a result of this missing functionality one needs to meticulously check every e-mail for whether it is encrypted as expected. More work. I sent countless unencrypted e-mails that should have been encrypted. So much for the end-to-end encryption in Thunderbird.

PS: The Q&A writes about decryption. However the intended use of e-mail per-recipient-rules was and still is encryption. Otherwise this feature would have been named per-senders-rules and we wouldn't have to "Please ensure that your encryption and digital signature settings apply..." I guess this is a mere documentation inconsistency.


The add-on Security Settings from Address Book basically does what you described for S/MIME.

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