---
type: source
title: "URZ: Encrypted Communication for Instant Messaging"
tags: [xmpp, encryption, otr, security]
related: [otr-encryption, adium, pidgin, xmpp]
created: 2026-06-30
updated: 2026-06-30
sources: ["output/rz_uni_greifswald_de_dienste_allgemein_instant_messaging_chat_verschluesselte_ko.md"]
---

# URZ: Encrypted Communication for Instant Messaging

This source provides technical instructions for implementing end-to-end encryption (E2EE) within the university's instant messaging services, specifically focusing on the XMPP protocol.

## Key Technical Guidance
- **Recommended Protocol**: The URZ recommends **Off The Record (OTR)** encryption.
- **Client Requirements**: E2EE requires both the sender and receiver to use OTR-capable clients and possess valid private keys.
- **Platform Recommendations**:
    - **Windows**: [[pidgin]] with the OTR plugin.
    - **Ubuntu**: [[pidgin]] with the `pidgin-otr` package.
    - **macOS**: [[adium]] (OTR is integrated).

## OTR Implementation in Pidgin
- **Activation**: Enabled via `Tools` > `Plugins` > `Off-the-Record Messaging`.
- **Key Generation**: A private key must be generated for the specific Jabber account in the plugin configuration.
- **Logging Policy**: By default, OTR conversations are not logged because logs are stored in plaintext on the local disk. Users must inform their partners if local logging is enabled.

## Authentication Workflow
To move a conversation from "Unverified" to "Private" status, bidirectional authentication is required:
1. **Question & Answer**: A secret question/answer known only to the partner (Pidgin-to-Pidgin only).
2. **Shared Passphrase**: A pre-shared password (Pidgin-to-Pidgin only).
3. **Manual Fingerprint Comparison**: Comparing the public key fingerprints (Universal method).
