[falcor84]

>The server is using MD5 hashes to determine if you uploaded the same file or if it should re-scan it

Wouldn't the sensible thing for a server that gets an upload matching an existing file's hash be to just treat it as an idempotent no-op? What reason would it have to replace the old version with a presumably identical copy? What am I missing?

[dnet]

I assume the scanner is a separate library/service that receives the contents and returns a boolean safe/malicious result, and the implementation using MD5 to avoid expensive re-scans is an internal detail hidden from the caller.