How to make PKCS conformation oracle for trying Bleichenbacher’s RSA attack? I was trying to understand Bleichenbacher’s CCA attack and thought of work it out in python. Can some one throw some light on the the logic behind the oracle used to check PKCS conformation? Will a cipher's parity check yield anything useful?
I unfortunately don't have enough reputation to comment, forgive the answer that is a link to another answer. Your question is explained well in this answer:

https://crypto.stackexchange.com/a/12706/17884