The Study And Applications Of The Convertible Authenticated Encryption Schemes

Since the first computer network was established in 1956, the technologies ofInternet have been developing very quickly. Nowadays, all kinds ofcommunications networks, such as PSTN, ISDN and mobile communicationsystems, have greatly changed our modes of life, and information and networksbecome more and more important in everyone's diary life. As a result, cryptology,networks and information security have been receiving extensive attentions andhave been applied to the fields of military, government, finance, communications,education, industry and etc.The main content of cryptology, networks and information security is toguarantee the confidentiality, authentication and integrity of the information beingtransmitted in a communication system. Confidentiality means privacy, whichcould protect the information from leaking to some illegitimate users.Authentication ensures the proper communication parties, which could protect thecommunication parties from being impersonated. Integrity could protect theinformation from being modified under any situation.In recent years, Internet has been infiltrated into human beings' lives becauseof its convenience and inexpensiveness, and has become an important method ofcommunication. Not only have all these brought convenience that has been neverseen before to human beings, but also have brought challenges, that is to say,Internet requires more security on information. Network is faced with varioussecurity threats, and it is important to effectively protect crucial data and toimprove the security of computer networks.Under the situation, network security has been more and more importantbased on avoiding information on network being attacked. We have consideredthat network security should be more and more critical.First, this paper introduces its research background and some conceptsconcerned with cipher. And then classifies the encrypt algorithms, emphasizes onseveral algorithms and their theories in common use. Put forward the concept ofdigital signature based on the encrypt algorithms, then introduce authenticatedencryption techniques and several convertible authenticated encryption schemeson pop. After discussing in detail, I fine out the shortage about them, I put forwardtwo convertible authenticated encryption schemes with semantic security.The two convertible authenticated encryption schemes with semantic security,which have the following characteristics: Each scheme could provide semanticsecurity for the message, that is, any adversary cannot determine whether hisguessed message is the actual message signed by the signer even if he gets a validsignature;After receiving a signature, the receiver could recover and then verifythe message by only using his secret key and the signer's public key;If the signerwants to repudiate his signature later, the receiver could prove the dishonesty ofthe signer to any third party by revealing the recovered message and some otherrelated parameters.