数字电视的条件接收系统

2006(03/04)CHINADIGITALCABLETV:TN949.197:B:1007-7022(2006)03-0238-05,(,610031):,,(CAS):;;DiscusstheConditionalAccessSystemofDigitalTelevisionJIANGYing2lian,CHENWei2rong(SouthwestJiaotongUniversity,SichuanChengdu610031,China)Abstract:TheriseofthedigitalTVenablespeopleappreciatethehigh2qualityTVprogram.WiththematurityofthedigitalTV,theconditionalaccesssystem(namelyCAS)getsgooddevelopment.Thistextmainlyintro2ducestheCASSdevelopment,basicfunction,securitymechanism,operationprincipleandsecurityrequire2ment.Keywords:digitalTV;conditionalaccesssystem;securemechanism1,,:(1),,68(2),,,,,(3),,,,(4),,,(5),,:(19792),,,;(19652),,,,832(6),,,(7)()(HDTVSDTVLDTV)(),,,(8),,,,2(CA)/,,STB,STBCACAS,CAS,CADTV,CA/3:(1),,(2),,,,(STB),(3),CAS,CAS,CADTV3CA,,,,,CA:3.1CAS(ChannelScrambing),,,CAS,1CAS,CAS,,:(1),CATV,,CAS,,(2)CAS,,,(3)CASCACATV,,STB,CA,,CAS(4)CA,CA,,CATV3.2CAS(ContentEncryption)CAS932200603/04:,CW(ContentWord:,),CW,CASCATV,CASDVB(DigitalVideoBroadcasting:,)(SimulCrypt)CASDVB,CAS,,STBCA,,,,PID(PacketIdentifi2er:),PID,3.3CAS(Multi2Encryption)STB,CAS,,,,,STB,STBCAS3.4CAS(AlgorithmRenewable)CASCASTB,DVB(MultiCrypt)OpenCablePOD(PointofDeploy:),,STBCAS,,,CAS,PODCA,CATV3.5CAS,CATVSBA(SoftwareDefinedBroad2bandAccess:),,I/O(/),DSP(,CPU),CACM(Ca2bleModem:)Modem()MPEG,CA,,,POD,,CASCA,,,(Platform)CAS,CA,,,CACACAS,4CA(1)(Subscription)(PPV)(IPPV),3,(2),,,GCA,(3)EMM(EntitlementManagementMessage)EMM,,OSD,;ID,,,,60s,,60s,,(4),042:200603/04,,ID,,,(5)PES(ProgramElementaryStream)TS(TransportStream),TS,(CW),CWPIDECM(EntitlementControlMessage);PES,,PIDECM,,(6),(7),,,(8),,,5CA,,,,,;(1),,DVB,TS,(CW),,,,ECMK1,1ECM,ECM,TS,ECM,CAEMMK1,EMMCWECMK1ECM,,,,ECM,,,,ECM,,,(),(PDK)PDKCA,CAPROM,,CAPDK6:(IMS)(PMS)(SMS)(CAS)(EPG)CA,26.1ASI/,CA,/,CA/,142200603/04:2CAPMTCAT/,CW,CWTS,CWECMG,ECMGECM,ECMCW,/ECMSCS,ECMTS,CW,CWEMMSITS,ECMEMMSITSASI,,6.2,TS,ECMEMM,ECMEMMECMEMM,,,CW,CWCW,CW,,7DVB(1),,,,(2),,,,(3),(ETSIISO),,,(4),(5),,,,,,,8,DVB,,DVB,,,:[1].[M].:,2002.[2]GY/Z175-2001,[S].[3],.[M].:,2005.[:2005209214]242:200603/04