Abstract: A system and method for detecting and thus preventing check fraud utilizing a digital computer with image capture and interpretation systems. The system converts the payee information, issue date and the MICR line information (account number, check number and dollar amount) to a check digit which is then placed into the MICR line of a check, printed on its face or transmitted via the paid issuance file to the drawee bank. The drawee bank, upon presentment utilizes a transformation algorithm to convert the printed payee information and issue date on the check into a numerical value that is combined with MICR line information and a check digit is calculated based upon pre-agreed logic. This unique data processing system quickly confirms properly presented checks while effectively precludes payee and other alterations in a cost effective manner.