Is C2 truly Zero Knowledge?

I know that the data is AES256 but is there any situation where that data can be recovered by someone other than myself? I was using in Canada because of the fact that they wouldn’t give any information for any reason. But I’d love to switch to C2 because it would work much nicer with my Synology(s). Just looking to get a discussion around “how comfortable are we with the Zero Knowledge claim.”

So if you are using C2 for hyperbackup you can just encrypt your data via hyperbackup before it ever leaves your NAS. You set an encryption key, that without that encryption key no one can recover your data, even if XYZ gov subpoenaed it.

This just leaves the question out of it because Synology never has the ability to screw something as they never even have you unencrypted data.

Excellent answer, thank you. I’m gearing to set this all up when volume encryption is ready in 7.2.