Build reproducibility doesn't solve the problem of "how do I know the computer I don't control is actually running the program I think it is?" The only solutio

Build reproducibility doesn't solve the problem of "how do I know the computer I don't control is actually running the program I think it is?" The only solutions are related to fully homomorphic encryption, which is a way of running a program on a computer you don't control where the operator of that computer cannot learn information about the work it is performing. Unfortunately, pure software approaches to FHE haven't been proven out. It is possible to get the benefits of FHE by utilizing a software enclave, but then you have a different trust narrative that involves hardware (and attestation services). The point of remote attestation is that you can verify that a computer you don't control is running a specific binary (verified by the hash and a signing key) at a specific moment in time. The problem is that the chain of trust for the signing key traces back to the manufacturer of the enclave. The holy grail would be some way of decentralizing the trust of the enclave OR finding a way to do purely software based FHE that was fast. I'm not holding my breath for the latter, but the former might be possible in the next decade. In short, if you have a reproducible build but you don't have a way of verifying that binary is actually running on a remote server you don't control, the reproducibility of the build is a moot point. I sorta think the only systems where build reproducibility matters today are ones that use enclaves (but I'm willing to be disabused of this notion if people feel otherwise).