1. A system comprising: at least one processor; and a memory storing instructions configured to instruct the at least one processor to perform: receiving event data comprising an unordered string set; assigning string set dictionary indexes for strings of the unordered string set in a string set dictionary; sorting the unordered string set to provide a sorted series based on the string set dictionary indexes for the unordered string set; computing a differential series from the sorted series; and encoding the differential series into binary code words.