數位微流體生物晶片因為低消耗、便利攜帶性和高效率的關係，在現今的健康照護產業中扮演著重要角色。根據最新的市場調查報告，生物晶片的市值成長率是往年的兩倍以上。然而隨著市值的巨大成長，利用侵權行為來獲取不法所得也成了一大威脅。為了防止侵權行為，傳統方法上是利用密鑰來授權。然而，數位微流體生物晶片上並沒有複雜的記憶體和邏輯閘來儲存密鑰，因此設計防護方法變得更加困難。在這篇論文中，我們提出了第一個利用最新物理不可克隆函數(PUF)來授權數位微流體生物晶片的防護方法。我們提出的物理不可克隆函數(PUF)利用了數位微流體生物晶片上固有的變異來生產密鑰，因此不需要使用記憶體。最後，我們分析了提出的方法的安全性，實驗也顯示出此方法的可行性。

Digital microfluidic biochips (DMFBs) play an important role in the healthcare industry due to its advantages such as low-cost, portability, and efficiency. According to the recent market report, the growth of biochips market is twice than before. However, as the enormous business opportunities grow, piracy attacks, which are exploited by unscrupulous people to gain illegal profits, become a severe threat to DMFBs. To prevent piracy attacks, the conventional approach uses secret keys to perform authentication. Nevertheless, DMFBs only consist of electrodes to control the operations of droplets, and there are no memories and logic gates integrated on it to store secret keys. This makes designing secure defenses of DMFBs against piracy attacks more difficult. Thus, in this paper, we propose the first authentication method for piracy prevention of DMFBs based on a novel Physical Unclonable Function (PUF). The proposed PUF utilizes the inherent variation of electrodes on DMFBs to generate secret keys, so it does not require memory. Experimental results demonstrate the feasibility of our proposed PUF. Finally, we analyze the security of the proposed method against piracy attacks.

Acknowledgement i
Abstract ii
1 Introduction 1
1.1 Digital Microfluidic Biochip and Security Issue . . . . . . . . . . . . . . . 1
1.2 IP Piracy Attack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Hardware Trojan Attack . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.4 Countermeasure and Contribution . . . . . . . . . . . . . . . . . . . . . . 2
2 Background 4
2.1 Digital Microfluidic Biochip (DMFB) . . . . . . . . . . . . . . . . . . . . 4
2.1.1 Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.2 Design Flow of DMFBs and Vulnerabilities . . . . . . . . . . . . . 7
3 Related Work 9
3.1 Bioassay Encryption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 DMFB Locking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.3 Checkpoint Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4 Security System of DMFBs 12
4.1 Threat Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2 Modified Design Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.3 Foundry System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.4 Security assessment of the security system . . . . . . . . . . . . . . . . . . 16
4.5 User System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.5.1 Activation Number Checking . . . . . . . . . . . . . . . . . . . . 18
4.5.2 Decision Making on Fatal Error . . . . . . . . . . . . . . . . . . . 22
4.5.3 Transportation Key . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.5.4 Mixing Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5 Experimental Results 24
5.1 IP Piracy Only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.2 Trojan Attack Only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5.3 IP Piracy and Trojan Attack . . . . . . . . . . . . . . . . . . . . . . . . . . 28
6 Conclusion 29
References 31

[1] Y. Zhao, T. Xu, and K. Chakrabarty, “Broadcast electrode-addressing and scheduling methods for pin-constrained digital microfluidic biochips,” IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, vol. 30, no. 7, pp. 986–999, 2011.
[2] C.-W. Hsieh, Z. Li, and T.-Y. Ho, “Piracy prevention of digital microfluidic biochips,” in Design Automation Conference (ASP-DAC), 2017 22nd Asia and South Pacific, pp. 512–517, 2017.
[3] F. Su, K. Chakrabarty, and R. B. Fair, “Microfluidics-based biochips: technology issues, implementation platforms, and design-automation challenges,” Proceedings of IEEE/ACM International Conference on Computer-Aided Design, vol. 25, pp. 211–223, 2006.
[4] R. B. Fair, “Digital microfluidics: is a true lab-on-a-chip possible?,” Microfluidics and Nanofluidics, vol. 3, pp. 245–281, 2007.
[5] R. Sista, Z. Hua, P. Thwar, A. Sudarsan, V. Srinivasan, A. Eckhardt, M. Pollack, and V. Pamula, “Development of a digital microfluidic platform for point of care testing,” Lab on a Chip, vol. 8, pp. 2091–2104, 2008.
[6] S. S. Ali, M. Ibrahim, J. Rajendran, O. Sinanoglu, and K. Chakrabarty, “Supply-chain security of digital microfluidic biochips,” IEEE Transactions on Computers, vol. 49, pp. 36–43, 2016.
[7] S. S. Ali, M. Ibrahim, O. Sinanoglu, K. Chakrabarty, and R. Karri, “Security assessment of cyberphysical digital microfluidic biochips,” IEEE/ACM Transactions on Computational Biology and Bioinformatics, vol. 13, pp. 445–458, 2016.
[8] F. Su, S. Ozev, and K. Chakrabarty, “Ensuring the operational health of droplet-based microelectrofluidic biosensor systems,” IEEE Sensors Journal, vol. 5, no. 4, pp. 763–773, 2005.
[9] M. Ibrahim, Z. Li, and K. Chakrabarty, “Advances in design automation techniques for digital-microfluidic biochips,” in Formal Modeling and Verification of Cyber-Physical Systems, pp. 190–223, 2015.
[10] M. Pollack, A. Shenderov, and R. Fair, “Electrowetting-based actuation of droplets for integrated microfluidics,” Lab on a Chip, vol. 2, pp. 96–101, 2002.
[11] S. S. Ali, M. Ibrahim, O. Sinanoglu, K. Chakrabarty, and R. Karri, “Microfluidic encryption of on-chip biochemical assays,” in Biomedical Circuits and Systems Conference (BioCAS), 2016 IEEE, pp. 152–155, 2016.
[12] J. Tang, M. Ibrahim, K. Chakrabarty, and R. Karri, “Secure randomized checkpointing for digital microfluidic biochips,” IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 2017.
[13] J. Dofe, Y. Zhang, and Q. Yu, “Dsd: a dynamic state-deflection method for gatelevel netlist obfuscation,” in VLSI (ISVLSI), 2016 IEEE Computer Society Annual Symposium on, pp. 565–570, 2016.