They don't use convergent encryption, they randomly generated keys when files are uploaded. The only deduplication that exists is when you copy a file that's be

They don't use convergent encryption, they randomly generated keys when files are uploaded. The only deduplication that exists is when you copy a file that's been shared with you by another user, because in this particular case you also copy the key. "Secure" isn't boolean. Although convergent encryption will prevent people from accessing your secret data, it does have different security properties: Mega would be able to determine whether you have a particular file, which they cannot with the current system.