Question

I am looking for instructions on how to configure the jenkins email plugin (ext-mail) to encrypt notifications? The uncle google did not help me too much.

Answer 1

such feature is not out-of-box, you need custom ExtendedEmailPublisher for your needs.

        MimeMessage msg = createMail(mailType, build, listener);
        Address[] allRecipients = msg.getAllRecipients();
        if (allRecipients != null) {
            StringBuilder buf = new StringBuilder("Sending email to:");
            for (Address a : allRecipients) {
                buf.append(' ').append(a);
            }
            listener.getLogger().println(buf);
            Transport.send(msg);
            if (build.getAction(MailMessageIdAction.class) == null) {
                build.addAction(new MailMessageIdAction(msg.getMessageID()));
            }
            return true;
        }

you can get Recipients and Email message for sign/encrypt and call Transport.send(msg) at last.