Very cool! Tangentially related, I looked into reimplementing `codesign` in Rust while I was at Mozilla. We wanted to see if we could take Apple hardware out of the loop for our release process after we had switched Mac Firefox builds to cross-compile from Linux. I got a bunch of code written and I'm pretty sure I could have made it work if I had gotten the go-ahead to spend time on it but then we heard about notarization and decided it wasn't worth the effort since Apple was going to require us to use their service anyway.