> What isn’t clear is what benefit the reproducibility provides. The only way to verify that the untrusted binary is bit-for-bit identical to the binary that wo

> What isn’t clear is what benefit the reproducibility provides. The only way to verify that the untrusted binary is bit-for-bit identical to the binary that would be produced by building the source code, is to produce your own trusted binary first and then compare it. At that point you already have a trusted binary you can use, so what value did reproducible builds provide? That's not the interesting case. The interesting case is when the untrusted binary doesn't match the binary produced by building the source code. Assuming that the untrusted binary has been signed by its build system, you now have proof that the build system is misbehaving. And that proof can be distributed and reproduced by everyone else. Once Debian is fully reproducible, I expect several organizations (universities, other Linux distribution vendors, governments, etc) to silently rebuild every single Debian package, and compare the result with the Debian binaries; if they find any mismatch, they can announce it publicly (with proof), so that the whole world (starting with the Debian project itself) will know that there's something wrong. This does not need any complicated consensus mechanism. > More often, attackers want signing keys so they can sign their own binaries, steal proprietary source code, inject malicious code into source code tarballs, or malicious patches into source repositories. In Debian, compromising the build server is not enough to inject malicious code into source code tarballs or patches, since the source code is also signed by the package maintainer. Unexpected changes on which maintainer signed the source code for a given package could be flagged as suspicious. The only attack left from that list, at least for Debian, would be for the attacker to sign their own top-level Release file (on Debian, individual packages are not signed, instead a file containing the hash of a file containing the hash of the package is what is signed). But the attacker cannot distribute the resulting compromised packages to everyone, since those who rebuild and compare every package would notice it not matching the corresponding source code, and warn everyone else.