Cofactor-based NPN boolean matching algorithm

This paper proposes an NPN Boolean matching algorithm under the transformation of input negation and/or input permutation and/or output negation. The algorithm utilizes the cofactor signature and Shannon expansion to search possible transformations, which reduces search space complexity and time complexity. The algorithm uses Binary Decision Diagrams (BDD) to represent Boolean function and compute cofactor efficiently. Experimental results demonstrate its effectiveness for NPN Boolean matching. It realizes NPN Boolean matching of 20-variable Boolean function.