Research On Security Of Two-Dimensional Code Based On Chaotic Mapping

The two-dimensional code technology is a latest bar code technology.Although it has a history of several decades,it has only been popular in recent years in China.Among them,the QR code has a large amount of information stored in it.It is the most successful two-dimensional code with the advantages of strong ability of embedding capability,error correcting,and easy to use.The research of this thesis is based on QR code.Chaotic systems have become an important tool in cryptography because they have the advantages of initial parameter sensitivity,randomness and unpredictability which are consistent with the characteristics of random number generation in cryptography.This thesis is to use chaotic maps to ensure the security of the following design.In this thesis,a two-dimensional code anti-counterfeiting system based on chaotic map is designed based on two-dimensional code technology and chaotic technology.In this anti-counterfeiting system,a Chebyshev map is used to generate a key pair of a chaotic public key cryptosystem.It uses its own public key to encrypt the unique identifier of the product and then concatenates it with the hash value of the unique identifier of the product and encodes it into a two-dimensional code printed on the package of the product.The merchants develop their own APP and build their own public key in their own app.The consumer purchases the product,scans the QR code on the product through the APP developed by the merchant,and obtains the unique identifier of the encrypted product and the hash identifier of the unique identifier of the product,and submits the data to the merchant server.The content of the data is used by the merchant.The key-encrypted encrypted serial number value of the unique identifier of the product and a random number.The random number is the secret key of the symmetric password.After the server receives the data,it decrypts the key that can obtain the unique identifier of the commodity and the symmetric password through its own private key.The server queries the database whether the unique identifier of the commodity is qualified,and the query result is encrypted and sent to the consumer APP using the symmetric key.After the consumer APP receives the result,the authenticity of the two-dimensional code is verified by whether the commodity unique identifier is consistent with the hash function value.This scheme is secure and can resist replay attacks and man-in-the-middle attacks.This thesis also designs a two-dimensional code lottery system based on chaotic map combining the above two technologies.The system mainly uses client and server interactions to generate a lottery result.First,the server generates a random number,sends the hash value of the random number to the user,and then the user generates a random number and sends it to the server.The server calculates the result of the lottery through a public chaotic drawing function using the random number generated by itself and the user-generated random number.The calculated lottery result and the random number generated by the server are sent to the user,and the user can use the hash function and the chaotic lottery function to verify whether the server is fraudulent.