> Next, I install signal on my phone via the app store. How do I know the app I installed matches the source code that was audited? After all, google / Apple co

> Next, I install signal on my phone via the app store. How do I know the app I installed matches the source code that was audited? After all, google / Apple could decide / be forced to provide a modified binary. Reproducible builds work for that. At least on iOS it would be very hard to get a hash of the binary running on your phone, not possible without jailbreaking AFAIK? You could check it on your computer of course, but what's stopping $vendor from having an device.id == rocqua's phone check when they deliver the binary to your phone? Further, doesn't (at least) Apple do something with the signatures causing the binary downloaded to actually be slightly different and missmatch the one uploaded by the developer? If you don't trust your OS and in extension (at least on very locked down platforms as iOS) your OS vendor, it's basically game over. I mean, they have root on your connected device and could easily change what binary is started, even if you could verify the copy you downloaded onto disk.