I am using standard encryption AES/CBC.
I wonder if I can invest some time adding my own custom encoding/decoding after the encryption just as an extra security layer.
Does it really add any value in case the public algorithm is broken and the key still not compromised?
Is unknown custom algorithm (encoding/decoding) secure because no one knows about it except me?
Can you please support with samples of attacks that may break my assumption?
I am aware how weak is Ceaser Ciphering. I am on this argument with a colleague. He is in favor of using AES then applying custom shuffling as extra protection.
My stand is that it does not add anything rather than performance toll. I can't seem to prove that argument, while he bases his on the fact that we are already using AES and that encoding would put extra effort on the attacker.
Thanks for the downvotes, it's a stupid question needs answers with solid proofs.