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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
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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)
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ANS: 數位調變 (Digital Modulation)
類比調變or數位調變?! ANS: 數位調變 (Digital Modulation)
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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
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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
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實體通道(Physical channel)
1Mbit/sec
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實體通道(頻寬共享)
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跳頻技術(Frequency Hopping)
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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
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Piconet Formation Page - scan protocol
to establish links with nodes in proximity Master Active Slave Parked Slave Standby
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Scatternet Formation
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Physical Link Types Synchronous Connection Oriented (SCO) Link
Slot reservation at fixed intervals Asynchronous Connection-less (ACL) Link Polling access method
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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
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潛在的危險
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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
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Initialization key E22 E22 IN_RAND IN_RAND IN_RAND PIN PIN L L Kinit
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Link key (1) Kinit Kinit K KA = Klink KA = Klink
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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
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Mutual authentication
ADDRB AU_RAND ADDRB ADDRB E1 E1 Klink Klink AU_RAND AU_RAND SRES ACO SRES ACO SRES
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Encryption key EN_RAND EN_RAND EN_RAND E3 E3 Klink Klink ACO ACO KC KC
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Key stream E0 E0 ADDRA ADDRA clockMASTER clockMASTER KC KC KCIPHER
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Encryption of data KCIPHER KCIPHER DATA DATA KCIPHER KCIPHER DATA DATA
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E N D
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