Detecting Subverted Cryptographic Protocols by Entropy Checking

What happens when your implementation of SSL or some other cryptographic protocol is subverted through a buffer overflow attack? You have been hacked, yes. Unfortunately, you may be unaware of it: because normal traffic is encrypted, most IDSs cannot monitor it. We propose a simple, yet efficient technique to detect most of such attacks, by computing the entropy of the flow and comparing it against known thresholds

GNU Radio

GNU Radio is a free & open-source software development toolkit that provides signal processing blocks to implement software radios. It can be used with readily-available, low-cost external RF hardware to create software-defined radios, or without hardware in a simulation-like environment. It is widely used in hobbyist, academic, and commercial environments to support both wireless communications research and real-world radio systems