The Messenger Security Review
Endpoints · Linked devices
German customs investigators have been reading WhatsApp, Signal and Telegram since the end of 2023 with no malware and no attack on the cryptography. They add a second device to your account. The maths never fails — and that is the problem.
13 September 2026 · ~5 min
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Account takeover · Linked devices
A French government alert this March describes an account takeover that needs no exploit whatsoever: you are asked to scan a QR code, and the code enrols a device that is not yours. There is a second road in the same alert, and it is worse.
13 September 2026 · ~6 min
Targeted attacks · Social engineering
State-linked actors have spent the past year going after the Signal and WhatsApp accounts of European officials. Throughout, the cryptography did precisely what it promises.
13 September 2026 · ~6 min
Identity · Key verification
Encryption protects a conversation between two public keys. Deciding that those keys belong to the people you meant is a different problem, it has never been solved comfortably, and in August 2026 Signal shipped the most serious attempt so far.
13 September 2026 · ~6 min
Cryptography · Post-quantum
A key-encapsulation mechanism hands you one shared secret. A conversation needs a fresh one forever, in both directions, over a network that drops and reorders.
13 September 2026 · ~7 min
Endpoints · Post-compromise security
Post-compromise security is a real, provable property of a key schedule, and it is worth having. It also only exists if the ratchet actually turns — ours did not — and it stops at the edge of the device, every time.
13 September 2026 · ~7 min
Metadata · Traffic analysis
A messenger can encrypt content perfectly and still hand an observer who talks to whom, when, how often and from where. That residue is not a footnote to the threat model.
13 September 2026 · ~6 min
Policy · Client-side scanning
Europe has spent four years trying to write a law that detects illegal content inside conversations nobody can read. The cipher survives every draft.
13 September 2026 · ~7 min
Endpoints · Key management
One device is a solved problem. Add a laptop, a tablet and the phone you replaced last year, and the hard part stops being the cipher: it becomes bookkeeping.
13 September 2026 · ~7 min
Architecture · Identity and metadata
Signal, WhatsApp, Telegram, Olvid, SimpleX, Session, Briar, Matrix. They agree almost completely on how to encrypt a message and disagree completely on what has to be true before one can be sent — which is the part that decides what a subpoena gets.
13 September 2026 · ~8 min
AI · Endpoints and plaintext
AI reached encrypted messaging from two directions at once: as the thing writing the convincing message, and as the helpful feature that has to be handed the plaintext before it can help. Only the second one is a design decision you get to make.
13 September 2026 · ~8 min
About the notes under each article. They are open to anyone, with no account and no name, and nothing is stored about the person writing — no address, no browser string. They are also published immediately, without review, so they are capped at 160 characters and a link typed there is never made clickable.
