Abstract: The present invention provides various techniques for encoding hidden information in checks and other security documents. The hidden information provides an authentication tool. In one implementation, we provide a method for encoding a security document with information. The security document includes a substrate having printing thereon. The information is hidden in the printing and corresponds to text or numbers conveyed by at least a portion of the printing. The method includes dividing the information into a plurality of payload sets, wherein each payload set includes a sub-set of the information, and encoding the payload sets across the substrate. The plurality of payload sets is concatenated in order to retrieve the information.