1. A system, process and method for detecting whether content within a given document is common to content within a plurality of other, existing documents, the system, process and method comprising: a character string recognizer for recognizing character strings in the content of the given document; a character string distinguisher for distinguishing main character strings and auxiliary character strings in the recognized character strings by reference to a closed list of main character strings; an encoder for encoding the content of the given document by assigning the main and auxiliary character strings differently using one or more digits; and a matcher for matching a plurality of n-digit streams from within the encoded content with any corresponding n-digit streams within previously-encoded content of the one or more other documents.
11. The system, process and method of claim 1 , wherein the matcher post filters any matches to perform a similarity computation measure.