What Is the Difference Between Forgery and Counterfeit? Both forgery and counterfeiting are crimes involving fraud.Forgery, deceive or injure another, he falsely makes, completes or alters a written instrument which is or purports to be. Under our law, a person is guilty of Forgery in the Second. Forgery and Fraud Crimes. Third Degree Forgery: NY Penal Law 170.05.