Telegram¶

Best suited for: Communities without a requirement to hide text from the service. [1] [2]
Avoid if…: You want to hide cloud text from the provider. [1]
Main strength: Mainstream community features. [1] [2]
Main weakness: Does not protect cloud text from the provider. [1] [2]
Account identifier: Required phone number; optional username. [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: Provider can process cloud messages and metadata. [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: Civil production under seal in India; fields and scope partly contradictory. [1]

E2EE: Cloud Chats / groups are not E2EE; separate device-bound Secret Chats. [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: Provider can process cloud messages and metadata. [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: Direct or relayed calls depending on setting / network. [1] [2]
Relay / TURN: Unknown: not established for the version and configuration in question.
Calls: Documented calls; their network path must be distinguished from messaging. [1] [2]
Groups: Cloud groups are not E2EE. [1] [2]

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: Does not protect cloud text from the provider. [1] [2]
Public law-enforcement evidence: Civil production under seal in India; fields and scope partly contradictory. [1]

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.