1. A method for document-to-template matching for data-leak prevention (DLP), the method comprising the steps of: (a) providing a document as a stream of characters; (b) splitting said stream into a plurality of non-overlapping serialized data lines, with each said serialized data line including at least two side characters; (c) calculating a hash value for each said serialized data line; (d) checking for each said hash value in a hash map of a template set; (e) determining a similarity match to a particular template based on a predefined threshold of template hash values, of said template set, being found in said stream; and (f) based on said similarity match, executing a DLP security policy for said document.