Weighted Visual Cryptography Based On QR Code

Quick Response(QR)code is currently the most widely used bar code.Its advantages,such as large data capacity,comprehensive reading and self-correction capability,make it having broad application prospects and development space.However,the current QR code is mainly used to store public information.Anyone can identify and read the information therein,which is a security defect for QR code.The security defect makes QR code inappropriate for storing secret message.This thesis proposes a weighted visual cryptography based on QR code,which aims to improve the convenience of sharing and accessing of secret information.Furthermore,it also improves security of QR code.Based on the error correction capability of QR code,and combined with the scheme of visual cryptography,a weighted(n,n)type visual cryptography scheme is designed.The secret information in a secret QR code is split into a plurality of QR codes used as camouflage.After embedding the secret information,the camouflage QR codes are called share QR codes.The share QR code has the same appearance as an ordinary QR code,but the secret information is stored therein.By scanning a single share QR code,one can only obtain the camouflaged information but not the secret information.The secret QR code can be reconstructed by simply combining all the share QR codes by XOR operation,and the secret information stored therein can be obtained by scanning and decoding the reconstructed QR code.This solution solves the defect that the QR code can only store public information.In order to further improve the security,we divide the weights of the QR codes into different values,so that the amount of secret information stored in the QR codes of different weights can be different.Therefore,the contributions of share QR codes with different weights will be different when combining them.The QR code with a higher weight stores more secret information and has larger contribution when recovering the secret information.In addition,we also designed a QR code with special weight that has a special effect on restoring secret information.All the QR codes need to be combined with this share QR code having special weight after their own combination.The combination can correctly reconstruct the secret QR code,but the special share QR code itself does not contain any secret information.Furthermore,we design a more generalized weighted(k,n)type share QR code scheme.The experimental results show that the generated QR code can store secret information and its appearance is the same as ordinary QR code.It verifies that this scheme can solve the security defect.The weighted QR codes can be used for secret sharing,which expands the application scenario of QR codes and provides a safer and more convenient method for secret sharing.