[kramerger]

These are GIT repositories, they have their own cryptographically unique identifiers. No need to send your data to a third-party to get it confirmed.

Maybe I'm missing something, but this whole operation feels like a huge infrastructure paid by Google for something that is not needed.

[ratorx]

> cryptographically unique

Git uses SHA1 which is pretty far from cryptographically secure. It’s unlikely that’s the sole reason for having a separate checksum database though.

[justinclift]

Doing some searching around online, it seems like git introduced sha256 support several years ago.

[dharmab]

Only for some local operations- git protocol still uses SHA-1 for compatibility with old clients, and existing SHA-1 objects in old repositories aren't converted.

[dharmab]

Git history can be rewritten or deleted e.g. by the git rebase command. The mirror's checksum DB is independent and prevents your build from breaking or being altered if a dependency is manipulated or deleted.

As sibling comment notes, Git's hashes are not secure: https://shattered.it