http://degate.zfch.de/

Probably the best open source suite out there. Recommend building it on the recommend OS setup, think its Ubuntu 8.10 or something as I had trouble building it elsewhere.

bitbucket.org/spramod/bsim-tetc14/overview

Implements the following paper algos. Provides aggregation and function inference scheme, but doesn't reach behavioural HDL level.

• Reverse Engineering Digital Circuits Using Functional Analysis (Pramod Subramanyan): http://www.academia.edu/2909575/Reverse_Engineering_Digital_Circuits_Using_Functional_Analysis