The detection of counterfeits using a CDP relies on an "information loss principle", which states that every time a digital image is printed or scanned, some information about the original digital image is lost. A CDP is a maximum entropy image that attempts to take advantage of this information loss. Since producing a counterfeit CDP requires an additional scanning and printing processes, it will have less information than an original CDP. By measuring the information in the scanned CDP, the detector can determine whether the CDP is an original print or a copy.
