According to this article, “…files are encrypted on the hard drive…”, which implies some form of encryption-at-rest on data stored in a Cozy. However, according to this forum entry, “…we chose to not encrypt every data.…”, which implies that the data are not encrypted.
Would it be possible to have further information on how the data is secured on Cozy’s servers? In particular, is Cozy Drive zero-knowledge? If not, what isn’t encrypted and why? What encryption libraries and techniques are being used?