Encryption Scheme Of Distributed Multipoint Multimedia Conferences Using IDEA And RSA Algorithms

With the rapidly development of computer network technology and the widely use of network technology in every walk of life , People transmit data through computer network more and more frequently, including all kinds of secret information (for example,military secret; bussiness secret;personal private information) .Today, as a result of poor security of our network system, we can not prevent the transmittied information from stealing and modifying unlawful.Thus,the computer network technology is applied to our daily life restrictedly .Recently, many network applications with VoIP (for example MSN Messenger ; DialPad ; Distributed multipoint multimedia conferences) take no measures to encrypt their data ! When People purchase and use these network product , they are not aware of some hacker or organization are intercepting; stealing ; modifying their information through network without any resistance . With the knowledge of computer network security widespread , the demand for security communication become more and more imminence. The developer of network application are confronted with big challenge.Firstly, this paper discuss symmetry cipher algorithms?IDEA and public key cryptography桼SA. IDEA is better than RSA in efficiency of encrypt and decryption the other hand, RSA is better than IDEA in key management .Both two algorithms are Safety. IDEA can not implement digital signature and authentication but RSA can in theory.Secondly, this paper put forward an encryption scheme which combining the strongpoint of two algorithms. It's basic principle :before transmitting data ,we encrypt message with IDEA key and sign or encrypt IDEA key with RSA .when communicating ,we encrypt voice payload with IDEA session key .when finished communications we destroy IDEA session key.Lastly, this paper give a realization of distributed multipoint multimedia conferences using this encryption scheme .this system include: local key management module key server module encrypt/decrypt module WinSocket module and other module, this system solve the problem of security communication in distributed multipoint multimedia conferences system effectively.