---
type: source
title: "URZ: Sign and Encrypt with Mozilla Thunderbird"
tags: [email-security, smime, thunderbird]
related: [thunderbird-smime-usage]
created: 2026-06-30
updated: 2026-06-30
sources: ["output/rz_uni_greifswald_de_dienste_allgemein_e_mail_e_mail_sicherheit_cert_thunderbird.md"]
---

# URZ: Sign and Encrypt with Mozilla Thunderbird

This source provides operational instructions for using S/MIME within the Mozilla Thunderbird email client at the Universität Greifswald. It focuses on the practical application of digital signatures and encryption after the initial certificate import.

## Key Instructions
- **Prerequisite**: Users must first import their certificate into Thunderbird (refer to [[thunderbird-certificate-import]]).
- **Digital Signing**: Once the certificate is imported, emails are signed automatically during the composition process, making them tamper-proof.
- **Encryption**: Encryption is an optional manual step. Users must select the **Verschlüsselung** (Encryption) button in the menu to encrypt the message.
- **Verification**: A small lock icon appears in the subject line of the email to indicate that it has been encrypted.
- **Management**: General S/MIME functions are accessible via the **S/MIME** button in the menu.

## Support
Technical issues are handled by the [[universitatsrechenzentrum-urz]] via their ticket system (hosted on [[groupware]]) or the campus hotline (ext. 1420).