Sat solver sha256. For the full 64-round SHA-256, the maximum gap is 386,767. I would like to share my work in the hope that others could give feedback, improve it, and maybe learn from it. I tried pre-image attacks with a SAT solver (z3 Theorem Prover), as well as a novel approach with a learned Bayesian network and loopy belief propagation. Nov 27, 2020 · Solvers from the major players like Gurobi, Cplex, and coin-or work well (much like the SAT solvers) until 17 rounds of SHA-256. Jul 1, 2024 · In the process, we demonstrate that these computer algebraic techniques can dramatically improve the performance of the SAT solver, enabling the SAT+CAS solver to find a semi-free-start collision of SHA-256 with 38 steps, while a plain SAT solver could go no further than 28 steps. Below, we can see that the number of INV and AND gates grow relatively linearly, at the same rate, as the number of rounds increases. Please note that this solver is designed to only work with specific SAT encodings, specifically the SHA-256 Collision Encoder by Saeed Nejati. For a SAT solver, this could mean that it doesn't detect an invalid variable assignment until values have been propagated a long way. This repository contains my attempts at pre-image attacks on SHA-256, MD5, and BitCoin. Our hybrid SAT + CAS solver significantly outperformed a pure SAT approach, enabling us to find collisions in step-reduced SHA-256 with significantly more steps. Jul 22, 2025 · In this paper, we use a satisfiability (SAT) solver as a tool to search for step-reduced SHA-256 collisions, and dynamically guide the solver with the aid of a computer algebra system (CAS) used to detect inconsistencies and deduce information that the solver would otherwise not detect on its own. It tries to solve the following questions deterministically (with a SAT solver) and probabilistically (with Bayesian networks and loopy belief propagation): Given a SHA-256 hash, can one find the input used to generate the hash? Given a partially known hash input and constraints on the (unknown) hash output Jun 28, 2024 · Our hybrid SAT + CAS solver significantly outperformed a pure SAT approach, enabling us to find collisions in step-reduced SHA-256 with significantly more steps. Feb 3, 2013 · This is a brute force approach to something-like-a preimage attack on SHA-256. The sfs directory houses the files related to SFS collisions. Code is here. The process of mining consists of finding an input to a cryptographic hash function which hashes below or equal to a fixed target value. INV logic gates are encoded as equality constraints for the solver (B = 1 — A) and AND gates as 3 inequality constraints described previously. Using SAT + CAS, we find a 38-step collision of SHA-256 with a modified initialization vector -- something first found by a highly sophisticated search tool of Mendel, Nad, and Schläffer. Using SAT + CAS, we find a 38-step collision of SHA-256 with a modified initialization vector—something first found by a highly sophisticated search tool of Mendel, Nad, and Schläffer. . This repository contains files related to the step-reduced SHA-256 collision attack, specifically the SAT solver log files, encodings, and lists of collisions. In this section, we review our enhancement of algebraic fault attack that has been applied to SHA-1 and SHA-256 using a programmatic SAT solver [27] that enables us to solve AFA instances with much fewer number of injected faults. In the process, we demonstrate that these computer algebraic techniques can dramatically improve the performance of the SAT solver, enabling the SAT+CAS solver to find a semi-free-start collision of SHA-256 with 38 steps, while a plain SAT solver could go no further than 28 steps. The purpose of this project is to find SHA-256 semi-free-start collisions more efficiently than a pure CaDiCaL approach. ogje mmsievi alczei vcwb lrydk cimmqj qfxb eithq chz mfin