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WiMAX 安全子層於嵌入式系統下之探討與實現

WiMAX 安全子層於嵌入式系統下之探討與實現. The research and implementation of WiMAX security subsystem over an embedded system. Advisor: Dr. Kai-Wei Ke Speaker: Yen-Jen Chen Date: 06/24/2008. Outline. Introduction Overview of 802.16d Security Overview of 802.16e Security

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WiMAX 安全子層於嵌入式系統下之探討與實現

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  1. WiMAX安全子層於嵌入式系統下之探討與實現 The research and implementation of WiMAX security subsystem over an embedded system Advisor: Dr. Kai-Wei Ke Speaker: Yen-Jen Chen Date: 06/24/2008

  2. Outline • Introduction • Overview of 802.16d Security • Overview of 802.16e Security • IEEE 802.16-2004 Security Sublayer Implementation • System Architecture • Subsystem design • System flow • System over embedded system • System test • Conclusion and Future Work • References

  3. Outline • Introduction • Overview of 802.16d Security • Overview of 802.16e Security • IEEE 802.16-2004 Security Sublayer Implementation • System Architecture • Subsystem design • System flow • System over embedded system • System test • Conclusion and Future Work • References

  4. MAC Privacy Sub-layer • Provides secure communication • Data encrypted with cipher clock chaining mode of DES • Prevents theft of service • SSs authenticated by BS using key management protocol

  5. IEEE 802.16 Security Architecture

  6. IEEE 802.16 Security Process

  7. Authentication Key lifetime: 1 to 70 days , usually 7days SS →BS: Cert(Manufacturer(SS)) SS →BS: Cert(SS) | Capabilities | SAID BS →SS: RSA-Encrypt(PubKey(SS), AK) | Lifetime | SeqNo | SAIDList

  8. KEK = Truncate-128(SHA1(((AK| 044) xor 5364) Downlink HMAC key = SHA1((AK|044) xor 3A64) Uplink HMAC key = SHA1((AK|044) xor 5C64) Key Derivation

  9. Data Key Exchange

  10. Data Encryption

  11. 認證資訊(authentication information)X.509 certificate 授權請求(authorization request)X.509 certificate, capability, Basic CID AK exchange 授權答覆(authorization reply)encrypted AK, SAIDs, SQNAK,… 密鑰請求(key request)SAID, HMAC-Digest,… TEK exchange(每一個資料傳輸連線都必須先做此動作) 密鑰答覆(key reply)encrypted TEK, CBC IV, HMAC-Digest,… 資料交換(利用TEK加密) IEEE 802.16 Security Process BS SS 1.確認SS身分 2.產生AK, 並用憑證中的public key將之加密 將AK解開 1.利用SHA演算法驗證HMAC-Digest 2.產生TEK 3.由AK產生KEK用以加密TEK 1.利用SHA驗證HMAC-Digest 2.由AK計算出KEK以解開TEK HMAC-Digest：用以驗證資料的完整性

  12. Outline • Introduction • Overview of 802.16d Security • Overview of 802.16e Security • IEEE 802.16-2004 Security Sublayer Implementation • System Architecture • Subsystem design • System flow • System over embedded system • System test • Conclusion and Future Work • References

  13. Security Architecture

  14. WiMAX PKMv2 Protocol

  15. EAP authentication protocol • EAP is a authentication framework not a specially authentication mechanism • the four methods in 802.16e • RSA based authentication • One level EAP based authentication • Two level EAP based authentication • RSA based authentication followed by EAP authentication

  16. EAP authentication protocol • RSA based authentication • Use the PKMv2 RSA-Request、PKMv2 RSA-Reply、PKMv2 RSA-Reject、PKMv2 RSA-acknowledgement messages to get pre-PAK • Using the public key of SS to encrypt the pre-PAK and send back to SS • pre-PAK generates the PAK (Primary Authorization key) and EIK(EAP integrity Key) • PAK generates the AK

  17. EAP authentication protocol (Cont.) • RSA based authentication • EIK|PAK <= Dot16KDF (pre-PAK,SS MAC address | BSID | ”EIK+PAK” , 320) • AK<= Dot16KDF (PAK,SS MAC address | BSID | PAK|”AK” , 160)

  18. EAP authentication protocol (Cont.) • One level EAP based authentication • Using the authentication exchange message to get MSK (Master session key) • PMK<= truncate(MSK,160) • AK<=Dot16KDF(PMK,SS MAC Address | BSID | “AK”,160)

  19. EAP authentication protocol (Cont.) • Two level EAP based authentication • SS sent the PKEv2 EAP Start to BS • The first EAP negotiation will begin between BS and SS included the message of PKMv2 Transfer2(MSK) • After that BS will send the EAP-Success or EAP-failure. • If BS sent the EAP-Success then BS will send the PKMv2_EAP_Complete encrypted by EIK immediate • If SS gets the EIK and PMK successful then SS can verify the message • Otherwise the SS might get the EAP-failure or get no respond to show that BS is failure to authentication

  20. EAP authentication protocol (Cont.) • Two level EAP based authentication • After SS finished the first EAP negotiation successful ,the SS will send “PKMv2 Authenticated EAP Start” to start the second EAP negotiation • When BS got this message, BS will check the message by EIK. • If BS check ok then BS will start the second EAP negotiation, otherwise BS will think the Authenticated failure. • The related messages of PKM is protected by EIK in the second EAP negotiation • If BS and SS competed second EAP negotiation, then BS and SS can get the AK form PMK( pairwise authorization key) and PMK2

  21. EAP authentication protocol (Cont.) • Two level EAP based authentication • EIK|PMK <= truncate (MSK,320) • PMK2 <= truncate(MSK,160) • AK <= Dot 16KDF(PMK + PMK2, SS MAC Address| BSID|” AK” , 160)

  22. EAP authentication protocol (Cont.) • RSA based authentication followed by EAP authentication • First execute RSA-based authorization and execute the second round of Double EAP mode • EIK|PAK <= Dot16KDF(pre-PAK, SS MAC Address | BSID | “EIK+PAK”,320) • AK <= Dot16KDF(PAK⊕PMK, SS MAC Address| BSID |PAK “AK” 160)

  23. Key hierarchy in the 802.16e • TEK (Traffic Encryption Key) • TEK is generated by random number of BS • BS use the KEK to encrypt the TEK and send to SS • TEK is used to encrypt the message or data between BS and SS

  24. Key hierarchy in the 802.16e

  25. Key hierarchy in the 802.16e

  26. Outline • Introduction • Overview of 802.16d Security • Overview of 802.16e Security • IEEE 802.16-2004 Security Sublayer Implementation • System Architecture • Subsystem design • System flow • System over embedded system • System test • Conclusion and Future Work • References

  27. System Architecture

  28. System Architecture • Data Privacy subsystem • Get the data form different system • Verify the data if encrypt or decrypt • Dispatch the data to the subsystem • Authentication subsystem • Verify the certification • Add the relative information • Generate the AK (New one or Update old) • Key Management subsystem • Save the information of the key (TEK KEK HMAC etc.) • Use AK to Generate key (KEK HMAC) • Generate the TEK (New one or Update old)

  29. Outline • Introduction • Overview of 802.16d Security • Overview of 802.16e Security • IEEE 802.16-2004 Security Sublayer Implementation • System Architecture • Subsystem design • System flow • System over embedded system • System test • Conclusion and Future Work • References

  30. Subsystem design • Data Privacy Subsystem

  31. Subsystem design • Authentication Subsystem

  32. Subsystem design • Key management Subsystem

  33. Outline • Introduction • Overview of 802.16d Security • Overview of 802.16e Security • IEEE 802.16-2004 Security Sublayer Implementation • System Architecture • Subsystem design • System flow • System over embedded system • System test • Conclusion and Future Work • References

  34. System flow

  35. System flow • Uplink Flow

  36. System flow • Downlink Flow

  37. Outline • Introduction • Overview of 802.16d Security • Overview of 802.16e Security • IEEE 802.16-2004 Security Sublayer Implementation • System Architecture • Subsystem design • System flow • System over embedded system • System test • Conclusion and Future Work • References

  38. System over embedded system

  39. System over embedded system • Central Controller Communication • Layered Communication

  40. System over embedded system • Class Diagram

  41. Outline • Introduction • Overview of 802.16d Security • Overview of 802.16e Security • IEEE 802.16-2004 Security Sublayer Implementation • System Architecture • Subsystem design • System flow • System over embedded system • System test • Conclusion and Future Work • References

  42. System test

  43. System test

  44. System test • Note: 140.124.183.50為SS端IP，140.124.183.220為BS端IP，140.124.183.230為relay node IP • Number 1047 and 1054，show that SS send the first cert to BS • Number 1060 and 1092，show that BS send the ACK to BS • Number 1259and 1260，show that SS send the second cert to BS • Number 1454and 1455，show that BS send the ACK to BS • Number 1998and 1999，show that SS send the TEK-REQ to BS • Number 2458 and 2459，show that BS send the TEK to SS

  45. Outline • Introduction • Overview of 802.16d Security • Overview of 802.16e Security • IEEE 802.16-2004 Security Sublayer Implementation • System Architecture • Subsystem design • System flow • System over embedded system • System test • Conclusion and Future Work • References

  46. Conclusion and future work • The System success portingover embedded system • Provide the security sublayer module of 802.16d and part of 802.16e • Porting the CPS of MAC over embedded system • Add the authentication of 802.16e

  47. Outline • Introduction • Overview of 802.16d Security • Overview of 802.16e Security • IEEE 802.16-2004 Security Sublayer Implementation System • System Architecture • Subsystem design • System flow • System over embedded system • System test • Conclusion and Future Work • References

  48. References • IEEE Standard for Local and metropolitan area networks Part 16:Air Interface for Fixed Broadband Wireless Access Systems，IEEE Std 802.16-2004 • IEEE Standard for Local and metropolitan area networks Part 16:Air Interface for Fixed and Mobile Broadband Wireless Access Systems，IEEE Std 802.16e-2005 • Johnson, David and Walker, Jesse of Intel (2004), “Overview of IEEE 802.16 Security” ,published by the IEEE computer society • http://www.seas.gwu.edu/~cheng/388/LecNotes2006/ • WiMAX 安全問題之研究 ,孫宏民、陳帥名、蕭英助 ,資通安全專論 T96006 • IEEE 802.16e-2005 WiMAX安全子層初探, 邱錫彥;陳彥學;王瑞堂;劉家蓁, 電腦與通訊, 119期, 2007/03

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