Boolean matching is a powerful technique that has been used in technology mapping to overcome the limitations of structural pattern matching. The current basis for performing Boolean matching is the computation of a canonical form to represent functions that are equivalent under negation and permutation of inputs and outputs. In this paper, we first present a detailed analysis of previous techniques for Boolean matching. We then describe a novel combination of existing methods and new ideas that results in a matcher which is dramatically faster than previous work. We point out that the presented algorithm is equally relevant for detecting generalized functional symmetries, which has broad applications in logic optimization and verification