From Kai E: https://support.mozilla.org/en-US/user/kaie/ No, we don't support it at this time. However, there's a workaround you could use. You could enable the feature which I had described here: https://thunderbird.topicbox.com/groups/e2ee/Tdc427a8b0255b85a The feature is available in the Thunderbird 115.x stable release, however, it still needs to be explicitly enabled, by changing preference mail.openpgp.passphrases.enabled to true, as described in that article. One you make that change, you can view the properties of your own key, and set a passphrase. Afterwards, every time you click an encrypted message, Thunderbird will prompt you to enter the passphrase to allow decryption. If you don't want decryption, you can cancel the prompt. (We intend to add a cache in the future, to make it more convenient to use the passphrase, without having it to enter every time. That work is tracked in https://bugzilla.mozilla.org/show_bug.cgi?id=1834577 - If you use the workaround, you'll have to set the timeout to 0 in the future, after we implement bug 1834577.)