Rewrite main search routine

It is a bit more clear, but this doesn't actually fix the issue I was
having.
A 0 byte is not valid padding, reject it!

And this is the root cause of the decryption issues on the padding
oracle attack. Now it works!
Fix off by one error in random index
Change the random seeds, problem 17 is solved

Sanity check for me that everything still works with different key, iv,
and plaintext.