近年來，物聯網( Internet of Thing, IoT )的蓬勃發展，遍佈於工業、農業、醫療、城市以及家庭，生活周遭無所不見物聯網的產品，大量的數據穿梭於各個網路，在未來數據的量更是會倍數的成長。而安全性問題，也是目前物聯網最重視的議題之一。於物聯網中，裝置對裝置(Device to Device, D2D)或是機器對機器(Machine to Machine,M2M)的訊息傳輸技術非常多種，最常見且方便使用的是訊息序列遙測傳輸(Message Queuing Telemetry Transport, MQTT)，在使用MQTT通訊協定時，其數據保密及安全性問題須加以考慮。由於MQTT通訊協定是為了資源有限的設備而設計的，相較於其他協定本身的安全性較於薄弱，為了提升安全性需要額外的演算法加以輔助。鑒於資源有限設備的運算能力，不能使用過於複雜的加密系統。因此本篇論文結合屬性加密( Attribute-Base Encryption, ABE )與混沌系統(Chaos System)的特性，提出一新的混沌同步屬性加密(Chaos Synchronization Attribute-Based Encryption, CS-ABE)系統並應用於MQTT通訊協定，實現比以往更佳安全的資料保密方式。最後我們實作出一套微型物聯網，設計與模擬資源有限的裝置，搭配人機介面與監聽軟體，展現出 MQTT 的通訊功能與混沌同步屬性加密的演算法的可行性及有效性，並在未來能應用於智慧家庭等智慧環境的資料保密。

MQTT protocol is designed for the resource-constrained devices, so its security is not stronger enough than the other communication protocols. To enhance MQTT security, it needs additional function to overcome its weakness. Considering the resource-constrained devices’ limited computation abilities, it cannot use too powerful or complicated cryptographic algorithm. This thesis studies and combines both Attribute-Based Encryption (ABE) and Chaos System with their respective characteristics to propose a new cryptographic algorithm, Chaos Synchronization Attribute-Based Encryption (CS-ABE), in MQTT, and to enhance the MQTT security.
Key words：Message Queuing Telemetry Transport (MQTT)、Attribute-Base Encryption ( ABE )、Chaos System

[1] B. Bouhdid, W. Akkari, A. Belghith, "A survey on the challenges and opportunities of the internet of things (IoT)", Computer Systems and Applications (AICCSA) 2017 IEEE/ACS 14th International Conference, 2017.
[2] OASIS, MQTT Version 3.1.1 Plus Errata 01, December 2015. (http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/mqtt-v3.1.1.html)
[3] Adil Bashir and Ajaz Hussain Mir, "Securing Publish-Subscribe Services with Dynamic Security Protocol in MQTT Enabled Internet of Things", International Journal of Security and Its Applications, vol. 11, No. 11, pp. 53-66, 2017.
[4] M. Singh, R. Ma, S. Vl, P. Balamuralidhar, "Secure MQTT for Internet of Things (IoT)", Communication Systems and Network Technologies (CSNT) 2015 Fifth International Conference, 2015.
[5] N. Naik, "Choice of effective messaging protocols for IoT systems: MQTT CoAP AMQP and HTTP", Proc. IEEE Int. Syst. Eng. Symp (ISSE)., pp. 1-7, Oct 2017.
[6] X. Wang, J. Zhang, E. Schooler, M. Ion, "Performance evaluation of Attribute-Based Encryption: Toward data privacy in the IoT", Communications (ICC) 2014 IEEE International Conference, pp. 725-730, June 2014.
[7] Adi Shamir, "Identity-based cryptosystems and signature schemes", Advances in Cryptology, Springer Berlin Heidelberg, 1985.
[8] A. Sahai and B. Waters, "Fuzzy Identity Based Encryption", Advances in Cryptology– Eurocrypt, volume 3494 of LNCS, pp. 457–473, Springer 2005.
[9] J. Bethencourt, A. Sahai and B. Waters. "Ciphertext-policy attribute-basedencryption." Proceedings of the 2007 IEEE Symposium on Security and Privacy ser. SP '07, pp. 321-334, 2007.
[10] Goyal, Vipul, Omkant Pandey, Amit Sahai and Brent Waters. "Attribute-based encryption for fine-grained access control of encrypted data." Proceedings of the 13th ACM conference on Computer and communications security, 2006.
[11] B. S. Adiga, M. A. Rajan, R. Shastry, V. L. Shivraj, P. Balamuralidhar, "Lightweight IBE scheme for Wireless Sensor nodes", Advanced Networks and Telecommuncations Systems (ANTS) 2013 IEEE International Conference, pp. 1-6, Dec 2013.
[12] Pecora, L.M., Carroll, T.L., "Synchronization in chaotic systems", Phys Rev Lett, vol. 64, pp. 821-824, 1990.
[13] Chen, Y.Q., Wang J., Cui, S.G., Deng, B., Wei, X.L., Tsang, K.M., "Chaos synchronization of coupled neurons via adaptive sliding model control", Nonlinear Analysis：Real World Application, vol. 12, pp. 3199-3206, 2011.
[14] Jeong, S.C., Ji, D.H., Park, J.H., Won, S.C, "Adaptive synchronization for uncertain chaotic neural networks with mixed time delays using fuzzy disturbance observer", Applied Mathematics and Computation, vol. 219, pp. 5984-5995, 2013.
[15] N. Oualha, K. T. Nguyen, "Lightweight attribute-based encryption for the Internet of Things", Proc. 25th Int. Conf. Comput. Commun. Netw., pp. 1-6, Aug 2016.
[16] M. Bafandehkar, S. M. Yasin, R. Mahmod, Z. M. Hanapi, "Comparison of ECC and RSA Algorithm in Resource Constrained Devices", Proc. IEEE Int. Conf. on IT Converg. and Secur (ICITCS)., pp. 1-3, Dec 2013.
[17] S. Ding, C. Li, H. Li, "A novel efficient pairing-free CP-ABE based on elliptic curve cryptography for IoT", IEEE Access, vol. 6, pp. 27336-27345, 2018.
[18] A. Beimel, ‘‘Secure schemes for secret sharing and key distribution,’’ Fac.Comput. Sci., Technion-Israel Inst. Technol., Haifa, Israel, 1996.
[19] K. D. Young, V. I. Utkin, U. Ozguner, "A control engineer's guide to sliding mode control", IEEE transactions on control systems technology, vol. 7, no. 3, pp. 328-342, 1999.