An improvement for PDF417 code authentication on mobile phone terminals based on code feature analysis and watermarking

In the current digital information age, PDF417 code has become an indispensable tool in daily life because it is extensively used. By the universal use of PDF417 code applications, mobile code scanning has become an indispensable part of people’s lives. Before scanning a PDF417 code, it is extremely important to confirm the security of the two-dimensional code, thus we need to take the necessary means to authenticate the two-dimensional code. Many researchers have proposed a digital watermarking algorithm that combines binary image watermarking technology and PDF417 code technology in view of the poor anti-counterfeiting performance of PDF417 codes. These algorithms can effectively resist replication, forgery and tampering attacks. However, these algorithms are limited to the use of mobile phone applications and cannot be integrated into mobile phones, which brings inconvenience to users. Therefore, this paper proposes a watermarking algorithm for PDF417 codes which is suitable for mobile terminal detection. First, based on the characteristics of PDF417 codes, the algorithm finds the appropriate boundary position to embed the watermark information and the watermark information is used for pixel inversion. Then, the geometrically distorted image of PDF417 obtained from the mobile phone is preprocessed and corrected into a relatively standard PDF417. Finally, the watermark information is extracted by the boundary error calculation. The theoretical analysis and experimental results show that the watermark which is embedded by this method can be extracted by mobile phone.