Research And Application Of Digital Signature Based On An Improved Hybrid Technology

This paper puts forward an improved hybrid digital signature technoloty based onanalyzing and researching of various encryption/decryption techniques and varioustypes of digital signature technology.There are two innovation in this improved scheme:(1)In this signature scheme,in order to ensure the data confidentiality,integrity andavailability during transmission,the use of a symmetric key cipher algorithms DES.Theadvantage of this algorithm is that perform fast and the algorithm is very suitable forlarge amounts of data to encryption/decryption.But S-box is the core of the DESalgorithm and the only non-linear component and its design idea has not beenreleased.So many experts and scholars think that there are some backdoors about itsdesign and easily to be attacked.So this thesis make improvements to the using order ofeight S-boxes.Based on the fractal theory,a optimization algorithm is used to constructthe evolution of S-box’s design.This scheme uses Kiwhich is DES algorithm’s each typeof sub-key to change the using order of S-boxes such that each round of iterationfunction F using the S-box’s sequence is not the same.This method can improve therandomness of the S-box,which increasing the security of the DES algorithm.(2)ElGamal public key algorithm based on a complex finite domains by thedifficulty of computing discrete logarithms.Although security of the algorithm has beengreatly improved, but because there are a lot of reverse mould in the signature andverification calculation stage,perform slower in the computer and the efficiency islow.So using a random function to generate a random number d and replaced with asimple modular arithmetic modular inversion.The aim is to reduce the burden on systemoperation and to improve the overall computing speed.Under the premise of providingthe same security this scheme to the requirements of system resources is lower.In addition,by adding the secure hash algorithm SHA-512in the improvedsignature scheme.The algorithm not only can greatly improve the speed of signature andverification but also can enhance to improve the security of the signature scheme.This improved hybrid digital signature algorithm is applied to networkperformance management system.Through the system test, the algorithm can guaranteethe authenticity and integrity of student performance in the network transmission and the security of this system in the network.And it can prevent unauthorized personnelposing as instructors forge or tamper with the students’ achievement.At the same time italso can prevent the instructors to deny their actions.