A novel CAPTCHA based on digital image information hiding

It is a normal method that CAPTCHA is used to distinguish general users from software robots in E-Business website. With the rapid development of reCAPTCHA, traditional simple CAPTCHA is facing the challenge of being cracked, while too complicated CAPTCHA is difficult for users to identify. This paper proposes a novel CAPTCHA based on digital image information hiding, which is easy for users to identify while hardly cracked by the robots. Theoretical analysis and simulation experiments indicate that this method is effective and safe.