Conditional-Affine Redundant Clauses for SHA-256 Differential SAT

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Standard Tseitin encodings of the SHA-256 nonlinear functions Ch and Maj can hide conditioned differential projections from Boolean Constraint Propagation (BCP). We materialize them as short, semantically redundant CNF clauses. A cofactor theorem characterizes all controlled differential linear forms; its implemented unit-vector specialization returns exactly all minimum-control projections, yielding four Ch and twelve Maj clauses per bit. The clauses preserve models, introduce no variables, and