oof. Quite a bit to digest there. In practice I don't really see how that replaces the process of verifying through another channel to verify that the person on the other side of the conversation is the expected person. It could have been Mallory you've been talking to from the beginning.

Using a very few selected companies as auditors feels like an odd decision. I'd have rather preferred some kind of web-of-trust like CAcert.org does.

And then there is the final nail in the coffin:

> When Automatic Key Verification is turned on, the Signal client periodically fetches Merkle tree heads from the Signal key transparency server. The client requires that each tree head belong to a lineage endorsed by all registered auditors within the last seven days. If the server does not present valid auditor signatures, the client will raise a warning and Automatic Key Verification will fail. A fully malicious server may therefore maintain a split view of the system for at most one week before client applications start to display warning messages.

(from https://blog.trailofbits.com/2026/08/11/how-trail-of-bits-he...)