Abstract: A system and method for proving forgery of digital file using a smart phone proves whether digital file recorded as digital evidence is tampered after the digital file is created, and is used in digital forensic and criminal investigation by proving that the digital file is not forged through the forgery confirmation system, and the digital file is used for substituting for notary fee, and used as data for proving a situation in an incident, data for proving foundation works after building construction, or evidence data for voice file in a threatening case. Since content transmitting information while using smart phone is stored as digital data through screen capture and a list of applications executed before the capture is converted and stored as hash value, the digital information authentication system through smart phone screen capture confirms actual facts thereafter by proving that the corresponding content is an original copy.