System and method for analyzing a target object for similarity to classes of reference objects. A first and a second set of attributes of the target object is identified composed respectively of attributes having values that are common, and variable, among a class of similar objects. A first hash is computed representing the first set of attributes according to a first hashing algorithm that is sensitive to variations in the first set of attributes among the class of similar objects. A second hash representing the second set of attributes is computed according to a second hashing algorithm that is insensitive to variations in the second set of attributes among the class of similar objects. An aggregate representation of the target object that is based on the first hash and the second hash is generated.