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I got asked to look at this SAT solver for SHA256. SAT solver's are a long running attack on SHA256, with slowly increasing partial success. This paper published a massive gain. The problem is that they did not actually attack SHA256. Naming their toy algorithm with no security features "SHA256" and then attacking their toy algorithm is not honest. Are there attacks effective? Yes. Did they attack SHA256? No. This is fundamentally dishonest. Here is a quote: "As mentioned, we've found a collision across the full 64 rounds with sr=59, corresponding to 43/48 schedule equations." What they should have said: "We created a collision across the weakened 64 rounds with sr=59 by removing most of the security features. This weakened algorithm had 43/48 schedule equations." The real "security" of SHA-256 comes from Modular Addition (Z=( X + Y ) mod 2^w) and the Message Schedule Expansion. Message schedule on page 3. Addition Modulo page 8. https://t.co/PSMEZpnHGf Dishonest SAT, not SHA256: https://t.co/FS2NznqWbo