A fast policy classification method and system. A policy differentiator can be provided which can include a policy repository configured to store hierarchical policy classification trees. The policy differentiator further can include a hashing module configured to produce integer values for string based selector attributes. In one aspect of the invention, the hashing module can include a longest string hashing function. A policy matching engine can be provided which is configured to locate policy rules in the hierarchical policy classification trees according to the integer values produced for the string based selector attributes. Finally, a policy matching engine interface can be provided through which policy queries and resulting policy decisions of the policy matching engine can be communicated between the policy matching engine and the policy enforcement entity.