Mobile Agent Homomorphic Encryption Algorithm Based On Active Protection

Mobile agent is a new intelligent program for large-scale distributed applications,possessing good application prospects in the field of active network protection, network management and e-commerce. Security of mobile agent is the problem to be resolved urgently.The difficulty of research is protecting the security of MA and its information not being stolen.Homomorphic encryption is based on mathematical problem, cryptography technology computing complexity theory. It is different from the traditional data encryption and allows to operate encrypted data without the decryption algorithm and decryption key, which has the same decrypted results compared with the direct results in plaintext state. Mobile agent protection method is an effective measure for mobile agent active protection technology based on homomorphic encryption. Assume that the mobile agent is constituted by the arithmetic operation, if there is a secure homomorphic encryption scheme can achieve all cryptographic calculations, the mobile agents' encryption computing problems can be resolved effectively.Currently, the research of homomorphic encryption is still in its beginning, and has the following disadvantages: the encryption strategy of existing homomorphic encryption is only restricted to integer; through analyzing ciphertext decimals, size, and positive and negative information encrypted, the plaintext decimals, size, and positive and negative information may be found, resulting in leakage of plaintext.In this paper, Aiming at these shortage above, results Obtained are as follows: ElGamal algorithm based on the homomorphic encryption algorithms of real domain is proposed.presentation methods of real domain is introduced. Confidentiality computing of elementary computing are realized, Shortage of encrypted data leaking the decimal sign and magnitude relations is overcome. The problem of positive integer only could be encrypted by EIGamal homomorphic encryption algorithm is solved. The improved algorithm can resist plaintext attack known, decimals and negative information could not be leaked, and noninteractive confidentiality calculations is realized. Mobile agent protection strategies are proposed based on composite function and addition-multiplication homomorphism encryption technology.The idea of these strategies is from the mobile cryptography proposed by Sander and Tschudin. In this dissertation, the MA is encrypted with FnC and addition-multiplicationhomomorphism encryption strategy, which is an extension to the idea of mobile cryptography.The encrypted MA can execute tasks on any hosts without decryption, and the encrypted MA and results are decrypted on the original host. This shows that the goal of MA protection is indeed achieved. The security of the scheme is validated and the feasibility and effectiveness of the scheme is verified.