Briar¶

Best suited for: Two Android contacts when offline resilience matters. [1] [2] [3] [4]
Avoid if…: You use iPhone, need calls or seamless multi-device. [1] [2] [3] [4]
Main strength: Android resilience without Internet, Tor and proximity exchange. [1] [2]
Main weakness: No iOS or calls; essential maintenance since July 2026. [1] [2]
Account identifier: Local identity; contacts in person or through invitation. [1] [2]
iOS: No official client established in the study. [1] [2]
Android: Yes, client listed in the study. [1]
Windows: Beta; desktop-specific limits. [1] [2]
macOS: Beta; desktop-specific limits. [1] [2]
Linux: Beta; desktop-specific limits. [1] [2]
Confidence and scope: Scope-limited audits; essential maintenance only since July 2026 and a separate beta desktop client. [1] [2]

What your contact learns¶

What the contact learns: The contact receives messages and the profile you share, and can keep a copy. [1] [2]

What the provider learns: No single central service; peers and transports remain in the model. [1] [2]

What the network / ISP learns: The network sees destinations, timing and volume; Tor or a relay changes the observer. [1] [2]
Apple / Google exposure: Store, installation and push can create metadata; exact profile linkage depends on the OS and was not tested here. [1] [2]
Public law-enforcement evidence: No individual disclosure case established here; this does not prove an absence of requests or data. [1] [2]

E2EE: E2EE; Tor and local Android transports. [1] [2]
Forward secrecy: Unknown: not established for the version and configuration in question.
Post-compromise security: Unknown: not established for the version and configuration in question.
Key verification: Unknown: not established for the version and configuration in question.

Metadata exposure: Less centralisation; local / Tor network and endpoints remain observable. [1] [2]
Global user ID: No single central account; local identity. [1] [2]
Username / discovery: Unknown: not established for the version and configuration in question.
Push notifications: Unknown: not established for the version and configuration in question.

IP exposure to peer: Tor or local transports; no calls; global correlation remains unresolved. [1] [2]
Relay / TURN: Tor / bridges or local Bluetooth / Wi-Fi depending on Android scenario. [1] [2]
Calls: No established voice calls. [1] [2]
Groups: Unknown: not established for the version and configuration in question.

Multi-device: Separate Android and beta desktop clients; desktop does not provide an iPhone client. [1] [2]
Backups: Unknown: not established for the version and configuration in question.

Audits: Cure53 and ROS/OTF: bounded dates, versions and retests in the register. [1] [2] [3]
Source code and binaries: Repositories and component-specific scopes recorded in Phase 2; no current binary rebuilt bit-for-bit here. [1] [2]
Main weakness: No iOS or calls; essential maintenance since July 2026. [1] [2]
Public law-enforcement evidence: No individual disclosure case established here; this does not prove an absence of requests or data. [1] [2]

Recommended configuration: Control devices, identities, notifications and files; verify client, version and calling path. [1] [2]
Remaining unknowns: Current network behaviour, distributed binaries and forensic evidence remain incomplete; check version, OS and configuration. [1] [2]

End-to-end encryption — E2EE

Participants’ devices control content keys. The transport server should not read ordinary messages. Learn more

Metadata

Data around the exchange: accounts, IP, timing, volume, devices or groups. Learn more

Pseudonymity

Use an identity different from your civil identity. It can still be linked to you. Learn more

Network anonymity

Reduce the ability to link traffic to your network address or its destination. Learn more

The detailed evidence is maintained in the French Phase 2 register. The translation is a restatement, not new evidence.