README.md

Bleichenbachers "Million Message Attack" on RSA

This repo contains two python projects to demonstrate Daniel Bleichenbacher's million message attack against RSA encryption and PKCS #1 padding.

PKCS #1 Padding Oracle

The bleichenbacher oracle is implemented in Bleichenbacher_Oracle.

RSA Parity Oracle

The effects of leaking the LSB (the Parity-Bit) of an RSA plaintext is demonstrated via Parity_Oracle.

The code is mostly taken from Practical-Padding-Oracle-Attacks-on-RSA. Since we find it very helpful to understand the Bleichenbacher oracle, it is included here as well.

Good to know

• The python-crypto package is needed. Please install it.
• Text in Python 3 is always Unicode and represented by the str type. Binary data is represented by the bytes type. Please see http://eli.thegreenplace.net/2012/01/30/the-bytesstr-dichotomy-in-python-3 for further information.
• We had some trouble with type errors during development. Thus, many functions are type-checked via a custom decorator and special annotations. (We found this pattern to be very useful in many scenarios.)

Literature

• "Chosen Ciphertext Attacks Against Protocols Based on the RSA Encryption Standard PKCS #1" by Daniel Bleichenbacher.
• Practical-Padding-Oracle-Attacks-on-RSA