Improvement And Implementation Of Four_layer Encryption Mechanism In Digital Television Conditional Access System

With the rapid development of information technology, digital television services have been started. Digital television broadcast platform gives us a lot of attractive services, such as HDTV, Internet Access, Online Game, VOD, Electronic Commerce and so on.But, because of benefits, most of programs will not be free. So how to guarantee those payers can access services and others can't access will be the key of whether the digital television broadcast platform can be developed successfully.Conditional Access System is just such a system wich provides necessary technologies for digital television broadcast platform. It guarantees those payers can access corresponding services legally and others can't access.Now, Conditional Access System in China is not in good condition, the security of digital television broadcast platform is very weak. Mutilayer Encryption Mechanism is just a key technology which is used to guarantee the security of information transmission between CAS. This paper studies Muti_layer Encryption Mechanism, puts forward and realizes an improved Four_layer Encryption Mechanism. EMMG (Entitlement Management Message Generator) is one kernel module in CASs and Muti_layer Encryption Mechanism mainly acts on this module, so at the end of this paper I design and realize the EMMG module.