Lightweight Cryptography And Application In E-Cash System

With the development of the information age, the security of data and information in people's life is increasingly vulnerable to invasion and attack, so the network space security has been paid much attention all the time. Cryptography is an effective way to solve the problem of information security, in which the lightweight cryptography is a security and protection level higher and faster implementation of the password system. As an important tool in cryptography, digital signature plays an important role in electronic commerce.In this thesis, firstly, AES algorithm, RSA algorithm and Hash function are used to carry out lightweight. The performance analysis of the improved algorithm is given,and theoretical datas illustrate that the algorithm is efficiency. Then a new digital signature scheme is proposed, which is applied to the electronic cash payment system.As follows:(1) For symmetric cryptographic algorithm AES, in order to reduce resource consumption and realize the optimization of form, byte and inverse byte substitution using composite field arithmetic and mix columns and inverse mix column to the parameter matrix of the product;(2) For the non-symmetric cryptographic algorithm RSA, this thesis uses the three prime factor algorithm. Although the number of prime number is increased than traditional algorithm, the number of the prime number is reduced, and the selection efficiency is improved when selecting the big prime number. When the decryption is combined with the Chinese Remainder Theorem, finally the computation time has been reduced;(3) For the Hash function, a hash function is constructed based on the parallel MD mode with LFSR mode to achieve a higher efficiency in hardware implementation. Experimental data shows that the hardware consumption is significant improvement compared with another hash Toeplitz;(4) To construct the digital signature scheme, the hash function add the advantage of AES algorithm. Get a new hash and anti collision speed by XOR and AES in each iteration process. In the digital signature scheme uses three factor primeRSA and the remainder theorem, to reduce the computation of modular power, which makes the scheme not only safe but also efficient;(5) Based on the scheme of payment system using RSA blind signature, the structure of the digital signature scheme is applied to the electronic cash payment system. This scheme not only has unforgeability, untraceable, but also can eliminate the double spending concerns to the participants.