OPSEC¶
Protect devices, identities and files before changing the messenger. Use current OS/app versions, a strong lock, controlled backups, hidden notification previews and only your own linked devices. A disappearing message cannot prevent a recipient from copying it.
Do not reuse aliases, avatars, signatures or cloud accounts. Inspect photo/document metadata, authors, filenames and thumbnails. Consider voice, language and schedules. VPN/Tor move an observer; verify the actual path instead of assuming protection.
Signal¶
- Recommended configuration
- Visibility and discovery: Nobody; fresh username, neutral profile, verified Safety Number, relayed calls when needed. [1] [2] [3] [4]
- Main weakness
- Mandatory number known to the provider and telecom layer. [1] [2]
- Multi-device
- Primary iPhone; official desktops linked through the phone. [1] [2]
- IP exposure to peer
- Calls can be relayed; check the setting and actual network path. [1] [2]
SimpleX¶
- Recommended configuration
- Fresh profile, single-use invitation, no reused identity; TURN; deliberate iOS notification choice. [1] [2] [3] [4]
- Main weakness
- More multi-device friction; relays and notifications require care. [1] [2]
- Multi-device
- Documented mobile–desktop pairing on the same local network; desktop beta. [1] [2]
- IP exposure to peer
- Default TURN hides IP from the peer; P2P can reveal it. [1] [2]
Olvid¶
- Recommended configuration
- Verify identity / fingerprint out of band; assess licensing and history before adding a desktop. [1] [2] [3] [4]
- Main weakness
- No network anonymity; calls and multi-device require a licence. [1] [2]
- Multi-device
- Licensed multi-device; old history not automatically transferred. [1] [2]
- IP exposure to peer
- Documented TURN-only calls: IP hidden from the peer, visible to the relay. [1] [2]
Session¶
- Recommended configuration
- Check fixed version and retest; avoid P2P calls if the peer must not see your IP. [1] [2] [3] [4]
- Main weakness
- Protocol V1 attacks and unknown fix / retest status; calls expose IP. [1] [2]
- Multi-device
- Unknown: not established for the version and configuration in question.
- IP exposure to peer
- Beta P2P calls: IP exposed to peer and managed STUN/TURN. [1] [2]
Threema¶
- Recommended configuration
- Do not link phone or email without need; verify fingerprints and each client’s limits. [1] [2] [3] [4]
- Main weakness
- Desktop beta limits, account data and linkable purchases. [1] [2]
- Multi-device
- Desktop 2.0 beta: up to two computers, no PFS; older client depends on the phone. [1] [2]
- IP exposure to peer
- Check calling mode and relay per client and configuration. [1] [2]
Cwtch¶
- Recommended configuration
- Control devices, identities, notifications and files; verify client, version and calling path. [1] [2]
- Main weakness
- No iOS; niche ecosystem and more limited assurance. [1] [2]
- Multi-device
- Unknown: not established for the version and configuration in question.
- IP exposure to peer
- Messages through onion; no established calls; Tor does not defeat a global observer. [1] [2]
Briar¶
- Recommended configuration
- Control devices, identities, notifications and files; verify client, version and calling path. [1] [2]
- Main weakness
- No iOS or calls; essential maintenance since July 2026. [1] [2]
- Multi-device
- Separate Android and beta desktop clients; desktop does not provide an iPhone client. [1] [2]
- IP exposure to peer
- Tor or local transports; no calls; global correlation remains unresolved. [1] [2]
The detailed evidence is maintained in the French Phase 2 register. The translation is a restatement, not new evidence.