DIFFER is a new differential testing tool developed by Michael Brown for finding bugs and soundness violations in transformed programs. It combines elements from differential, regression, and fuzz testing to help users identify bugs in programs that have been altered by software rewriting, debloating, and hardening tools. In an evaluation of 10 software debloating tools, DIFFER discovered failures or violations in 71% of the transformed programs produced by these tools. This tool fills a critical need in post-transformation software validation by allowing users to test transformed programs against their original versions. DIFFER is application-agnostic and can be used for various transformation tools.
https://blog.trailofbits.com/2024/01/31/introducing-differ-a-new-tool-for-testing-and-validating-transformed-programs/