US Patent 10043073 Document authentication using extracted digital fingerprints

Methods and systems for detecting changes, alterations and forgeries in documents utilize digital fingerprinting. A set of documents of a given type that are known to be altered or forgeries are scanned and “fingerprinted” to build a forgery database. Suspect documents are scanned and the resulting fingerprint data is used to query the forgery database to look for matching records, although a match need not be exact. Matches may be counted and compared to a threshold number to assess a confidence that a document is forged or not. The fingerprinting may be directed to at least one authentication region of a document, and one or more features in a region may be incorporated into a fingerprint of the document.