Design And Implementation Of Security Chat Room Based On Digital Certificate

Along with the Internet's fast development and application, the chatroom as a place of communication is welcome by the users of network deeplyfor its convenience and immediacy. As a place of communication in thevirtual society, the chat room has many uses, almost applied to each aspect ofpeople's life, for example: communication, document transmission, resourcesshare etc. But the network chat room exists a lot of problems on securitycurrently, for example: the identity of user can't be authenticated, thepassword of user was usually guessed by the others, the information istransmitted by plain text, even if a lot of chat rooms provide the service ofsecret chat, the information is also probably wiretapped. Because of thesesecure problems, the chat room hasn't been abroad used in someorganizaitons such as business organizations, governments, troops whichrequest higher security for information.Although some products of security chat room have been appeared,these products don't provide all secure services at the same time, such asidentity authentication, secrecy of information and integrality of information.So the security chat room based on certificate makes up the shortages of thecurrent security chat room and makes the chat room provide better secureservices.The security chat room based on certificate makes use of digitalcertificate, the protocol of SSL and the advantages of current security chatroom products to carry out the secure services of identity authentication,secrecy of information and integrality of information. Make the chat roomprovide the services of secure communication on the basis of high efficiency,immediacy, low cost and easy use.The usage of security chat room based on certificate is simpleness,convenience, high efficiency. The only difference of security chat roombased on certificate and current chat room used in network is that the user ofchat room uses digital certificate to register and login. User logging on chatroom can not feel the process that the information is encrypted and decryptedwhen chatting. Although security chat room based on certificate uses thetechnique of Symmetry encryption to ensure the confidentiality of chatinformation, it can't affect the efficiency of chat greatly and the user feels theinformation is instant.The security chat room based on certificate can be applied in theorganizations of business organizations, governments and troops whichrequest higher security for information. Along with the fast generalization ofPKI, certificate has already got the extensive application in the businessorganizations, governments and troops. So it satisfies the basic conditionsthat the security chat room based on certificate can be generalized and used.The high request for security of information restricts the chat room'sgeneralization and usage in the business organizations, governments andtroops, but secure services that the security chat room based on certificateprovided can more availably ensure the security of communication.The security chat room based on certificate is based on C/Sconfiguration and is constituted with server module, client module and SSLmodule.1. Server module has the functions of handling user' registrationrequest and logon request, sending chat information and receivingchat information.2. Client module has the functions of registration, logon, sending chatinformation and receiving chat information, selecting chat object,secrecy chat, filtrating information.3. SSL module has the functions of identity authentication, encryptinginformation and decrypting information, MAC's creation andvalidation.The security chat room based on certificate discussed here improves thesecurity of chat room from 5 aspects below:1. Carry out identity authentication with digital certificate. Userregisters and logons with digital certificate. This method is easy foruser to use and can provide high level security ensurence at thesame time. Digital certificate is the user's testify. Only the user hasthe secret key with which the digital certificate's public keymatches. So we can carry out identity authentication with themethod that judging whether the secret key matches with the publickey.2. Ensure the security of chat information's transmission with thetechnique of symmetry encryption. In order to ensure the secrecy ofchat information and let the sender and the receiver know the chatinformation's plain text, we use the method that the sender sendschat information's cipgher text that is the result of encrypting plaintext with symmetry key to the receiver and the receiver decrypts thecipher text with the same symmetry key to get the plain text.3. Ensure the symmetry key's secure exchange with the technique ofasymmetry encryption.4. Ensure the integrality of information with Message AuthenticationCode (MAC). The MAC ensures the information can not betampered during transmission.5. Carry out secure communication with the protocol of SSL.The paper indicates two aspects need to improve in the end. One aspectis that how to add the hardware encryption equipments' support. The otheraspect is that how to improve the secrecy of chat information at the server.Let the server send the chat information to the client directly withoutdecrypting and encrypting chat information in order to let the server can notget user's chat information and improve the secrecy of chat information.