Digital image authentication helps to determine the authenticity of images used as evidence. As photo editing software and image compression are popular nowadays, digital image authentication software is a necessary tool to determine the authenticity of any image. It is important to note that tampered images are always detectable through forensic image analysis.
Expert identifies the authentication areas needed to verify the integrity of the image used as evidence using the following ways:
- File format analysis: Verifies if the image is a camera-original
- Global Analysis: Examines the image for global modifications: for example if we find traces of image resaving or resizing
- Local Analysis: Examines the image for local modifications: these are modifications which are only found in a specific area of the image
- Camera Identification: Applies a camera/photosensor identification tools to verify if the image has been taken by a certain camera or device.
The goal of the digital image authentication software is to authenticate the digital integrity of the image format. Throughout this process, experts examine the digital information embedded within the image to determine if it is consistent with what we would expect to see from an original. A system creates an original recording when it produces a 1st generation copy.
Digital integrity verification testing detects malicious editing and tampering. They also authenticate the images date/time stamp information. Authentication testing may reveal that the date/time stamp information is not accurate under certain circumstances.