Delta Chat¶

Best suited for: Email portability rather than network unlinkability as the priority. [1] [2]
Avoid if…: Your priority is network unlinkability and uniform E2EE guarantees. [1]
Main strength: Email portability and interoperability. [1] [2]
Main weakness: Email metadata; conversation-dependent E2EE assurance. [1] [2]
Account identifier: Email / chatmail address and local profile. [1] [2]
iOS: Yes, client listed in the study. [1] [2]
Android: Yes, client listed in the study. [1]
Windows: Yes, client listed in the study. [1] [2]
macOS: Yes, client listed in the study. [1] [2]
Linux: Yes, client listed in the study. [1] [2]
Confidence and scope: Scope-limited documentary evidence; production metadata and distributed binaries not experimentally verified. [1]

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: Email operator sees addresses, headers, timing and volumes. [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: Autocrypt; E2EE depends on contact and conversation. [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: Email operator sees addresses, headers, timing and volumes. [1] [2]
Global user ID: Unknown: not established for the version and configuration in question.
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: WebRTC calls may be P2P and disclose IP. [1] [2]
Relay / TURN: Unknown: not established for the version and configuration in question.
Calls: Unknown: not established for the version and configuration in question.
Groups: Unknown: not established for the version and configuration in question.

Multi-device: Unknown: not established for the version and configuration in question.
Backups: Unknown: not established for the version and configuration in question.

Audits: Unknown: not established for the version and configuration in question.
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: Email metadata; conversation-dependent E2EE assurance. [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.