Research On Key Technical Of Identity-Based Encryption And Application In Secure E-mail

In the Identity-Based Encryption (IBE) of public key encryption,public key could be arbitrary string which can be constructed by user's open identity information instead of acquiring by public key certificate. For this reason,IBE has caught much attention since its been put forward. But not until 2001,when Boneh and Franklin proposed the first secure and practical IBE, does a large amount of technique based on IBE has been proposed. And the research on key escrow is the key issue in it's application.Communicating via E-mail has become an important part of daily contact. However,due to the openness of internet,the E-mail transmitting on it will suffer all sorts of attacks.Therefor, designing a secure E-mail system is worthy of studying. This dissertation takes the research on key kscrow problem,and analyzes the protocol based on trusted authority(threshold sharing and multi-key user private key distribution protocol) and user select Ciphertext(CBE,CLPK).Reaching the conclusion that n KGCs are mutually independent ,and the system must bear the burden of generating n pairs of public and private keys while senders can not confirm whether they receive the receiver's public key or not.We also emphatically analyzes a typical private key distributing scheme based on one KGC and several PKAs introduced by B. Lee ,pinting out 3 problems of pivate key escrow, vulnerable to be attacked and scurity leak caused by the neglect of system fault. Thus presents improved scheme and proves its validity and security.At last,in the dissertation,we compare IBE with PKI. Introducing the application of IBE in E-mail system. Analyzing interaction modes and secutiry design of secure E-mail system based on IBE. Then,a required E-mail system is implemented with the help of this technique.also,the paper combine IBE with access control,and realize dynamic character and high scalability.