> pseudo encrypted, where the encryption is done using software that is also controlled by the adversary I'd say there's a very real use for this, though, whic

> pseudo encrypted, where the encryption is done using software that is also controlled by the adversary I'd say there's a very real use for this, though, which is that with mobile applications it's more complicated to compromise a software deployment chain than it is to compromise a server-side system. If you're a state-level attacker and you want to coordinate a deployment of listening capabilities on Signal, say, you need to persistently compromise Signal's software supply chain and/or build systems, and do so in advance of other attacks you might want to coordinate with, because you need to wait for an entire App Store review cycle for your code to propagate to devices. The moment someone notices (say, a security researcher MITM'ing themselves) that traffic doesn't match the Signal protocol, your existence has been revealed. Whereas for the telcos in question, it seems it was possible to just compromise a server-side system to gain persistent listening capabilities, which could happen silently. Now, this can and should be a lot better, if, say, the Signal app was built not by Signal but by Apple and Google themselves, on build servers that provably create and release reproducible builds straight from a GitHub commit. It would remove the ability for Signal to be compromised in a non-community-auditable way. But even without this, it's a nontrivial amount of defense-in-depth.