Secure Messaging Systems

🔑 Key Takeaway: For sensitive operational communications, prefer messengers with end-to-end encryption enabled by default and a threat model that matches the data shared.

Messaging defaults decide whether compromise of a server or operator yields plaintext. This page compares common tools by encryption posture so teams can pick channels that match risk.

Using secure messaging systems is crucial for protecting the privacy and integrity of your communications. Here are some popular messaging systems that offer end-to-end encryption and those that do not by default.

End-to-end encrypted messaging systems

1. Signal

   • Offers strong end-to-end encryption for messages, voice calls, and video calls.
   • Open source and highly recommended for secure communication.
   • Signal

2. Matrix/Element

   • An open standard for decentralized communication with end-to-end encryption.
   • Element is a popular client for the Matrix protocol.
   • Matrix / Element

3. WhatsApp

   • Provides end-to-end encryption for messages, voice calls, and video calls by default.
   • Owned by Meta (Facebook).
   • WhatsApp

4. Wire

   • End-to-end encryption for messages and calls
   • Open source with a strong focus on privacy.
   • Wire

Messaging systems without default end-to-end encryption

These messaging systems supposedly provide encryption for data in transit and at rest, but not end-to-end encryption for messages.

1. Telegram

   • Offers end-to-end encryption only for "Secret Chats".
   • Telegram

2. Discord

   • Does not offer end-to-end encryption for messages.
   • Discord

3. Zoom

   • End-to-end encryption for calls, but must be manually enabled.
   • Zoom

4. Slack

   • Does not offer end-to-end encryption for messages.
   • Slack

5. Microsoft Teams

   • Does not offer end-to-end encryption for messages.
   • Microsoft Teams

Prefer messengers that offer end-to-end encryption by default for sensitive operational traffic.

Further Reading

• Encryption overview: framework map and shared concepts
• NIST SP 800-175B: guideline for using cryptographic standards in the federal government (useful baseline references)
• OWASP Cryptographic Storage Cheat Sheet