1. A method for creating a document that allows for authenticating and verifying integrity of the document, the method comprising: receiving, by a processing device, an image of the document having an area of interest containing information that varies from other documents of a same type; segmenting, by the processing device, the area of interest on the document into a plurality of elements; obtaining, by the processing device, an average gray scale of each element; determining, by the processing device, a relative gray scale for each element by matching the average gray scale of each element of the area of interest to as closest element of a reference gradient strip having a plurality of gray scales; generating, by the processing device, a gray scale profile of the area of interest based on the relative gray scale for each element; inserting, by the processing device, the gray scale profile into an identifier; and printing, by a printing device, the identifier and the gradient strip on the document.