A method for maintaining security of scanned documents which monitors read operations and output operations of documents containing proprietary or confidential information. For example, every time it is determined that a scanned document includes proprietary or confidential information, unique identification data corresponding to the read operation is generated and stored in a secured storage unit. The unique identification data can later be used to trace the scanned document and retrieve the information regarding the particular read operation (e.g., user, time, machine used, etc.).