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1. Developing Quantum Trusted Platform Module (QTPM) to Advance IoT Security

   https://doi.org/10.3390/fi17050193  

   Xu, Guobin; Adetifa, Oluwole; Mao, Jianzhou; Sakk, Eric; Wang, Shuangbao (May 2025, Future Internet)

   Randomness is integral to computer security, influencing fields such as cryptography and machine learning. In the context of cybersecurity, particularly for the Internet of Things (IoT), high levels of randomness are essential to secure cryptographic protocols. Quantum computing introduces significant risks to traditional encryption methods. To address these challenges, we propose investigating a quantum-safe solution for IoT-trusted computing. Specifically, we implement the first lightweight, practical integration of a quantum random number generator (QRNG) with a software-based trusted platform module (TPM) to create a deployable quantum trusted platform module (QTPM) prototype for IoT systems to improve cryptographic capabilities. The proposed quantum entropy as a service (QEaaS) framework further extends quantum entropy access to legacy and resource-constrained devices. Through the evaluation, we compare the performance of QRNG with traditional Pseudo-random Number Generators (PRNGs), demonstrating the effectiveness of the quantum TPM. Our paper highlights the transformative potential of integrating quantum technology to bolster IoT security. 

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2. Let a Non-barking Watchdog Bite: Cliptographic Signatures with an Offline Watchdog

   https://doi.org/10.1007/978-3-030-17253-4_8  

   Chow, Sherman S.; Russell, Sherman S.; Tang, Qiang; Yung, Moti; Zhao, Yongjun; Zhou, Hong-Sheng (April 2019, IACR International Workshop on Public Key Cryptography (PKC 2019))

   We study how to construct secure digital signature schemes in the presence of kleptographic attacks. Our work utilizes an offline watchdog to clip the power of subversions via only one-time black-box testing of the implementation. Previous results essentially rely on an online watchdog which requires the collection of all communicating transcripts (or active re-randomization of messages). We first give a simple but generic construction, without random oracles, in the partial-subversion model in which key generation and signing algorithms can be subverted. Then, we give the first digital signature scheme in the complete-subversion model in which all cryptographic algorithms can be subverted. This construction is based on the full-domain hash. Along the way, we enhance the recent result of Russell et al. (CRYPTO 2018) about correcting a subverted random oracle. 

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3. Minimizing Regret with Multiple Reserves

   https://doi.org/10.1145/3355900  

   Roughgarden, Tim; Wang, Joshua R. (October 2019, ACM Transactions on Economics and Computation)

   We study the problem of computing and learning non-anonymous reserve prices to maximize revenue. We first define the M aximizing M ultiple R eserves (MMR) problem in single-parameter matroid environments, where the input is m valuation profiles v 1 ,…, v m , indexed by the same n bidders, and the goal is to compute the vector r of (non-anonymous) reserve prices that maximizes the total revenue obtained on these profiles by the VCG mechanism with reserves r . We prove that the problem is APX -hard, even in the special case of single-item environments, and give a polynomial-time 1/2-approximation algorithm for it in arbitrary matroid environments. We then consider the online no-regret learning problem and show how to exploit the special structure of the MMR problem to translate our offline approximation algorithm into an online learning algorithm that achieves asymptotically time-averaged revenue at least 1/2 times that of the best fixed reserve prices in hindsight. On the negative side, we show that, quite generally, computational hardness for the offline optimization problem translates to computational hardness for obtaining vanishing time-averaged regret. Thus, our hardness result for the MMR problem implies that computationally efficient online learning requires approximation, even in the special case of single-item auction environments. 

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4. On the Communication Complexity of Key-Agreement Protocols

   Haitner, Iftach; Mazor, Noam; Oshman, Rotem; Reingold, Omer; Yehudayoff, Amir (January 2019, Innovations in Theoretical Computer Science Conference)

   In a key-agreement protocol whose security is proven in the random oracle model (ROM), the parties and the eavesdropper can make bounded number of queries to a shared random function (an “oracle”). Such protocol are the alternative to key-agreement protocols whose security is based on “public-key assumptions”, assumptions that being more structured are presumingly more vulnerable to attacks. Barak and Mahmoody [Crypto ’09] (following Impagliazzo and Rudich [STOC ’89]) have shown the ROM key-agreement protocols can only guarantee limited secrecy: the key of any `l-query protocol can be revealed by an O(l^2 )-query adversary, a bound that matches the gap obtained by the Merkle’s Puzzles two-message protocol of Merkle [CACM ’78]. While this quadratic gap might not seem like much, if the honest parties are willing to work “hard enough” and given continuousness improvement in common hash functions evaluation time, this gap yields a good enough advantage (assuming the security of the protocol holds when initiating the random function with a fixed hash function). In this work we consider the communication complexity of ROM key-agreement protocols. In Merkle’s Puzzles, the honest parties need to exchange Ω(l) bits (ignoring logarithmic factors) to obtain secrecy against an eavesdropper that makes roughly l^2 queries, which makes the protocol unrealizable in many settings. We show that for protocols with certain natural properties, such high communication is unavoidable. Specifically, this is the case if the honest parties’ queries are independent and uniformly random, or alternatively if the protocol uses non-adaptive queries and has only two rounds. Since two-round key-agreement protocol are equivalent to public-key encryption scheme (seeing the first message as the public-key), the latter result bounds the public-key and encryption size of public-key encryption scheme whose security is proven in the ROM. 

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5. RPM: Robust Anonymity at Scale

   https://doi.org/10.56553/POPETS-2023-0057  

   Lu, Donghang; Kate, Aniket (April 2023, Proceedings on Privacy Enhancing Technologies)

   Mazurek, Michelle L; Sherr, Micah. (Ed.)

   This work presents RPM, a scalable anonymous communication protocol suite using secure multiparty computation (MPC) with the offline-online model. We generate random, unknown permutation matrices in a secret-shared fashion and achieve improved (online) performance and the lightest communication and computation overhead for the clients compared to the state of art robust anonymous communication protocols. Using square-lattice shuffling, we make our protocol scale well as the number of clients increases. We provide three protocol variants, each targeting different input volumes and MPC frameworks/libraries. Besides, due to the modular design, our protocols can be easily generalized to support more MPC functionalities and security properties as they get developed. We also illustrate how to generalize our protocols to support two-way anonymous communication and secure sorting. We have implemented our protocols using the MP-SPDZ library suit and the benchmark illustrates that our protocols achieve unprecedented online phase performance with practical offline phases. 

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