Research On The Information Hiding Technique For QR Barcode Image And Its Covert Communication System

2D barcode is a graphical image made up of white and black modules,which stores information in both horizontal and vertical directions.Compared with 1D barcode,2D barcode has its specialities including much higher informatio n density,and higher security.Quick Response Code(QR barcode)is one of the most common 2D barcode.It has strogner capabilities to encode Chinese characters,correct errors and automatically recognize.Thus,QR barcode is widely used in our daily life.However,QR barcode does not provide any security protection capability.Any user can download a QR code encoder to generate QR code freely.Malicious attackers might exploits the fact that QR barcode is only machine-recognizable to counterfeit users by artifically adding or changing QR barcode and deliberately encode malicious information.Because of the users' lack of security consciousness,there are lots of security issues brings from QR barcode.After analyzing the encoding/decoding principles and s pecifications of QR barcode and summarizing the critical security issues related with QR barcode,we researches on the security issue of QR barcode and its information hiding techniques.Specifically,the main work and contributions of this thesis are summ arized as follows.First,after analyzing the error correction(EC)mechanism and EC capabilities of QR barcode,a novel information hiding approach is proposed for QR barcode image by exploiting the error correction(EC)mechanism of QR barcode and the l east significant bit(LSB)-based matching.By comparing QR barcode image and natural capturing image,we conclude that for the information hiding technique which uses QR barcode image as carrier,the key is how to fully exploit the characteristics of QR barcode image.By considering that QR barcode has the mechanism of error detection and error correction itself,the data coding zone of QR barcode is selected for secret information hiding.To decrease the change of QR barcode image,secret information is hiding by combing with LSB-based matching and embedding in a pair-wise way.Experimental results show that the proposed approach has desirable transparency and data hiding capacity,which is closely related with the version and error correction level of QR barcode itself.Second,by considering the fact that QR barcode is popularly used in Android mobile phones,a Android-based covert communication system is designed by exploiting QR barcode.It is established on the open source Zxing.Zxing include the QR barcode encoder/decoder in Java.Thus,we make necessary modifications to it by adding the QR barcode-based information hiding and extraction functionalities.Experimental results show that the proposed QR barcode-based covert communication system achieves the anticipated purpose of secure communication.This is a useful attempt to introducing QR barcode image into practical covert communication.