US Patent 7028886 Method and system for duplicate commercial paper detection

In one embodiment, software for detecting duplicate commercial paper transactions is operable to identify a check identification code, such as a Magnetic Ink Character Recognition (MICR) code, from a commercial paper transaction, with the check identification code comprising a plurality of fields. The software determines a hash value based on at least a portion of the plurality of fields and verifies the authenticity of the MICR code based, at least in part, on the determined hash value.