Research And Implementation Of QR Code Anti-counterfeiting Algorithm Based On Improved DES Algorithm

QR code,also known as quick response code,is widely used in all walks of life due to its strong fault tolerance,high reliability,and easy recognition.It has become the most popular two-dimensional code at present.With the widespread use of QR codes,the security issues are becoming more and more prominent.Due to the openness of the QR code encoding rules and the unification of the standards,it has caused a slight lack of security and severely affected its application.Therefore,this paper mainly studies the anti-counterfeiting of QR codes.Based on the research status of anti-counterfeiting technology of QR codes,this paper selects the appropriate algorithm to encrypt information.Its main work is as follows:1)According to the problem that the DES algorithm is vulnerable to the exhaustive search attack,this paper presents an improved DES algorithm.Combining the DES algorithm with the hash function,the order of the subkeys of the DES algorithm is changed,so as to make it possible to achieve the one-time padding to some extent and achieve the goal of improving the security of the DES algorithm.Both the theoretical analysis and the experimental verification can prove that the improved DES algorithm has improved security.2)When using the improved DES algorithm to encrypt information,in order to further improve the security of information,the affine transformation is used to encrypt and decrypt the contents before and after the use of improved DES algorithm,thereby increasing the key space and making information more secure.3)Considering that the information encrypted by the improvedDES algorithm does not have the authentication function,the encrypted information is signed with the digital signature based on the RSA algorithm.In order to save space and accelerate the speed of RSA signature and authentication,this paper will use information obtained after encryption to generate the fixed-length message digest,and then use the RSA digital signature method to sign the generated message digest.Finally,the digital signature information together with the encrypted information is used for the QR code encoding.4)The information after a series of operations,such as improved DES algorithm encryption and RSA-based digital signature,is encoded according to the encoding rules of the QR code,to obtain the QR code graphics with the security and authentication functions.The DES algorithm is liable to suffer from exhaustive attack.This paper puts forword the improved scheme based on hash function to solve the defect.First,exclusive OR(XOR)is performed on the plaintext and the key.Then,according to the address calculation times in hash table,and combined with affine transformation,the improved algorithm determines the subkey order.So that different input plaintexts cause different subkey orders and the improved algorithm make up for the short length of key in DES algorithm,enhancing the security of DES algorithm.The improved DES algorithm is applied to the encryption of the encoded information,which enhances the confidentiality of the QR code and prevents information from being illegally obtained by irrelevant personnel.Under the premise of preserving the symbol characteristics of the QR code,the RSA-based digital signature is added to the encrypted information,so that the encoded QR code has the authentication function.The message digest formed during the RSA-based digital signature also increases the security of the information in a sense,thereby increasing the security of the QR code.