Reproducible builds 101:

You take source code - build it - get the exact same binary every time (bit-for-bit identical). If the output differs? Something sneaky happened (backdoor, tampering, supply chain attack). It's crypto's best defense against compromised deps or malicious updates.

The problem:
Even if builds are reproducible, how do you prove the full chain is legit? Source code, deps, build env, logs, final artifact... all need to be verifiable without trusting GitHub, npm, or any ce