Bluetooth 技術篇 藍芽技術如何傳輸資料 藍芽傳輸的安全性 第六組 吳哲榮
如何傳輸資料 1.信號與系統 類比調變與數位調變 2.設備位置(Device Addressing) 3.實體通道(Physical channel) 4.跳頻(Frequency Hopping) 5.時序同步(Master and Slave) 6.Piconet and Scatternet 7.資料傳輸形態(SCO and ACL)
ANS： 數位調變 (Digital Modulation) 類比調變or數位調變?! ANS： 數位調變 (Digital Modulation)
Why? 1.抗干擾能力佳 2.資料傳輸統合 3.數位編碼加密 - Encryption - 訊號只有0與1 - Data、Voice、Video 3.數位編碼加密 - Encryption
Device Addressing 1.BD_ADDR NAP(not important)+UAP(hopping)+LAP(unique) 2.AM_ADDR Active Member Address MAX：8 3.PM_ADDR Parked Member Address MAX：256 4.AR_ADDR required Parked Mode – to – Active Mode
實體通道(Physical channel) 1Mbit/sec
實體通道(頻寬共享)
跳頻技術(Frequency Hopping)
Master和Slave時序同步 確認Master與Slave有相同的time block 以Master的時序為準
Piconet Formation Page - scan protocol to establish links with nodes in proximity Master Active Slave Parked Slave Standby
Scatternet Formation
Physical Link Types Synchronous Connection Oriented (SCO) Link Slot reservation at fixed intervals Asynchronous Connection-less (ACL) Link Polling access method
藍芽的安全性(Security) 無線傳輸的潛在威脅 無線傳輸的安全加密
潛在的危險
藍芽的加密技術 1.Initialization key 2.Link key 3.Mutual authentication 4.Encryption key 5.Key stream 6.Encryption of data
Initialization key E22 E22 IN_RAND IN_RAND IN_RAND PIN PIN L L Kinit
Link key (1) Kinit Kinit K KA = Klink KA = Klink
Link key (2) E21 E21 E21 E21 LK_RANDA LK_RANDB ADDRA ADDRB LK_RANDA LKA LKB KAB = Klink KAB = Klink LKB LKA LK_RANDB LK_RANDB E21 E21 ADDRB ADDRA
Mutual authentication ADDRB AU_RAND ADDRB ADDRB E1 E1 Klink Klink AU_RAND AU_RAND SRES ACO SRES ACO SRES
Encryption key EN_RAND EN_RAND EN_RAND E3 E3 Klink Klink ACO ACO KC KC
Key stream E0 E0 ADDRA ADDRA clockMASTER clockMASTER KC KC KCIPHER
Encryption of data KCIPHER KCIPHER DATA DATA KCIPHER KCIPHER DATA DATA
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