Apparatus and method to verify the integrity of a digital image (i.e., deciding whether or not the entire image or just a portion has been tampered with, and/or finding the doctored area in the image). One first determines the imaging sensor's reference pattern noise, which serves as a unique fingerprint that identifies the imaging sensor that captured the image. To verify the integrity of the content in a region of the image, a correlation detector determines the presence or absence of the imaging sensor's reference pattern noise in that region, thereby verifying whether or not the image has integrity. The correlation detector can also find automatically one or more regions in the image that were tampered with.