I am using one tool which encrypts files before these are synced to the cloud. I just opened the encrypted file to see how it looks. Here are the top five lines: I am a bit surprised that algorithm name, key size, initialization vector and some other parameters are appearing in plain text (which seems to be the header). I contacted the company and they say even when these things are open, attacker cannot break the cipher. My argument is why this hint to be provided to the attacker. Awaiting expert comments.