The Algorithm's Security Research Of The Cryptography

Algorithms and protocols are two important parts of applied cryptography. The research of algorithms are methods that make data to encrypt/decrypt base on theories of mathematics and improve the methods to adapt to the modern of fast development of computer and network technique the request of safety. The research of protocols are also methods how use and match the various algorithms make them more fast,more safety,more complications of virtual operation of people. In this essay has description of algorithms and protocols in recent years. Furthermore, it also summarize the algorithms and protocols to improvement of ideas and direction of development in the future. Finally, it proposed to the algorithms and protocols of the relation how use the algorithms to improve the protocols and how use the protocols of ideas to improve the performance of algorithms.This paper as following:1. In this paper, we advance the variable plaintext function (VPF) can be more sensitive to the avalanche effect, as to effectively prevent the differential analysis attack and increase the security of MD5. By studying the differential analysis attacks on MD5 algorithm and fou- nd that the differential analysis attacks could be successful was due to the change of individu- al bits of message. The alteration had only a few influence on chaining variable, and these few differences could be rectified after continuative loops. So the collision was generated, and the avalanche effect of the original MD5 algorithm could not prevent differential analysis attack. To enhance the security of MD5 algorithm, the sensitiveness of the avalanche of the MD5 algorithm should be increased.2. In this paper, we advance the technology that improve the ECCS's safeness and keep its good property. The technology called"Elliptic Hyperbola Cryptography System (EHCS)". The EHCS has the same calculation complexity as the elliptic curve cryptography system (ECCS), but it has excellently randomness. So EHCS can improve cryptographic safeness in theory. The EHCS has more flexible operation mode than ECCS. Therefore, the EHCS can against the attack technology and improve information technology's safeness.The ECCS has more and more important role in the cryptography. Instead of traditional public key cryptography system that it is RSA.3. In this paper, we advance the mobile agents'protocol has an especial loop which is formed by three consecutive nodes. And it has a total verification in the end. So this protocol not only can defend mostly known attacks, especially multiple-colluded truncation attack, but also consume a few resources about system and network. The protocol of the security of free-roaming is the major problem which has not resolved totally, but it plays an important role in the mobile agents'security. Some scheme can avoid the two-colluded truncation attack, but can not avoid the multiple-colluded truncation attack or can not avoid totally. Others can avoid the multiple-colluded truncation attack, but they consume a lot of the system and network resources such as some use the third proxy or some data are too big in the network transmission.