1. 2003.03.31 (c) Mitsubishi Electric Corp. 1 User Scenarios & Security Considerations in APPAGG part 2/2 2003.03.31 Nobuhiro Kobayashi@Mitsubishi Electric Corp. n-koba@iss.isl.melco.co.jp

2. 2003.03.31 (c) Mitsubishi Electric Corp. 2 Solution Who grants the rights to the subject ? Who stores the rights ? How describe the rights ? Who authenticates the subject ? Who authenticates the object ? Who authorizes the subject ? (? Any other items ? )

3. 2003.03.31 (c) Mitsubishi Electric Corp. 3 Solution (cont.) Who grants the rights to the subject ? –Owner –(? default settings by manufacturer )

4. 2003.03.31 (c) Mitsubishi Electric Corp. 4 Solution (cont.) Who stores the rights ? –? each appliance –? Owner’s wearable appliance (ex. watch)

5. 2003.03.31 (c) Mitsubishi Electric Corp. 5 Solution (cont.) How describe the rights ? –? XML –? original format

6. 2003.03.31 (c) Mitsubishi Electric Corp. 6 Solution (cont.) Who authenticates the subject ? –Owner –? Owner’s wearable appliance –? each appliance –? Trusted third party

7. 2003.03.31 (c) Mitsubishi Electric Corp. 7 Solution (cont.) Who authenticates the object ? –Owner –? Owner’s wearable appliance –? each appliance –? Trusted third party

8. 2003.03.31 (c) Mitsubishi Electric Corp. 8 Solution (cont.) Who authorizes the subject ? –Owner –? Owner’s wearable appliance –? each appliance –? Trusted third party

9. 2003.03.31 (c) Mitsubishi Electric Corp. 9 Example. Rights List for watch Owner is John. Owner can turn on the lights. Owner can use the laptop. Rights List for watch Owner is John. Owner can turn on the lights. Owner can use the laptop. John grants the rights to his watch. Rights List for light Owner is John. Rights List for light Owner is John. John grants the rights to the light. command Turn ON the light. How to set the rights to the lights ? John’s wearable appliance “watch” has the rights list. The “watch” sends command to the light.

10. 2003.03.31 (c) Mitsubishi Electric Corp. 10 command A( watch )B( light )C( attacker ) command success replay attack normal attack Version 1

11. 2003.03.31 (c) Mitsubishi Electric Corp. 11 Solution (cont.) To protect from replay attack. –Use Random Number –Use HMAC ( Keyed-Hashing for Message Authentication) It is more lightweight than other cryptographic routines.

12. 2003.03.31 (c) Mitsubishi Electric Corp. 12 RN command RN command RN HMAC RN2 cannot replay attack start request command RN HMAC check command RN HMAC ERROR normal attack generate Random Number ( RN ). command RN HMAC key HMAC tmp key check Version 2 compute HMAC with key A( watch )B( light )C( attacker )

13. 2003.03.31 (c) Mitsubishi Electric Corp. 13 RN command RN command RN command RN HMAC RN doesn’t execute command start request command RN HMAC check command RN HMAC normal attack key HMAC tmp key check Version 2’ A( watch )B( light )C( attacker )

14. 2003.03.31 (c) Mitsubishi Electric Corp. 14 normal attack RN_A start request RN_A start request HMAC_B RN_B HMAC_B RN_B key HMAC tmp key check command RN_B HMAC_A key command RN_B HMAC_A HMAC tmp key check RN_A2 start request HMAC_B RN_B HMAC tmp key check ERROR HMAC_B RN_B RN_A start request RN_A2 start request HMAC_B RN_B attack detected Version 3 A( watch )B( light )C( attacker )

15. 2003.03.31 (c) Mitsubishi Electric Corp. 15 References Appliance Aggregation Architecture Terminology, Survey, and Scenarios http://www.hpl.hp.com/hosted/ggf/AppAggSurvery.doc, March 2003 http://www.hpl.hp.com/hosted/ggf/AppAggSurvery.doc terminology translation ( English Japanese ) http://www.ipa.go.jp/security/ciadr/word_idx.html http://www.ipa.go.jp/security/ciadr/crword.html http://www.sisnet.or.jp/sis/dokuhon/p10.htm http://www.ipa.go.jp/security/ciadr/word_idx.html http://www.ipa.go.jp/security/ciadr/crword.html http://www.sisnet.or.jp/sis/dokuhon/p10.htm

16. 2003.03.31 (c) Mitsubishi Electric Corp. 16 END Thank you.

17. 2003.03.31 (c) Mitsubishi Electric Corp. 17 NOT USE

18. 2003.03.31 (c) Mitsubishi Electric Corp. 18 Example. (cont.) Rights List for watch Owner is John. Owner can turn on the lights. Owner can use the laptop. Rights List for watch Owner is John. Owner can turn on the lights. Owner can use the laptop. Rights List for light Owner is John. Rights List for light Owner is John. John sets “secret key”. AA John sets “secret key” to the “watch” and the light. The “watch” make HMAC from the command by “secret key”, and sends the command and HMAC to the light. The lights make HMAC from the received command by “secret key”, and compares this HMAC and the received HMAC. John sets “secret key”. HMAC made by watch command Turn ON the light. command Turn ON the light. HMAC made by watch HMAC made by light compare the HMAC

19. 2003.03.31 (c) Mitsubishi Electric Corp. 19 Example. (cont.) AA To against “replay attack”, use 3 handshakes and random numbers. HMAC made by watch command Turn ON the light. command Turn ON the light. HMAC made by watch HMAC made by light compare the HMAC L R.N. HMAC_L (R.N.) Generate random number. HMAC_L (R.N.) HMAC_L (R.N.) compare the HMAC Session Start Request W R.N. HMAC_W (R.N.) Generate random number. HMAC_L (R.N.) HMAC_W (R.N.) HMAC_W (R.N.) compare the HMAC

20. 2003.03.31 (c) Mitsubishi Electric Corp. 20 Terminology translation ( English Japanese ) Impersonation, spoof なりすまし authentication 認証 replay attack 再送攻撃 eavesdrop 盗聴 encryption 暗号化 alteration 改ざん Integrity 完全性 hash ハッシュ message digest メッセージ・ダイジェスト digital signature デジタル証明 repudiation 否認（事後否認） non-repudiation 否認拒否 authorization 認可 access control アクセス制御 privilege control 特権制御 principal 認証をうける単位（ユーザ、ホスト、アプリケーション等）