arXiv subjects

Karim Eldefrawy

Publications and source records attributed to Karim Eldefrawy.

7 recordsLinked to original sources

arXiv2023

Entanglement-based Mutual Quantum Distance Bounding

Mutual distance bounding (DB) protocols enable two distrusting parties to establish an upper-bound on the distance between them. DB has been so far mainly considered in classical settings and for classical applications, especially in wireless settings, e.g., to prevent relay attacks in wireless authentication and access control systems, and for secure localization. While recent research has started exploring DB in quantum settings, all current quantum DB (QDB) protocols employ quantum-bits (qubits) in the rapid-bit exchange phase and only perform one-way DB. Specifically, the latest QDB proposals improve the initial ones by adding resistance to photon number splitting attacks, and improving round complexity by avoiding communication from the prover to the verifier in the last authentication phase. This paper presents two new QDB protocols that differ from previously proposed protocols in several aspects: (1) to the best of our knowledge, our protocols are the first to utilize entangled qubits in the rapid-bit exchange phase, previous protocols relied on sending individual qubits, not those from a pair of entangled ones; (2) our second protocol can perform mutual QDB between two parties in one execution, previous QDB protocols had to be executed twice with the prover and verifier roles reversed in each execution; (3) the use of entangled qubits in our protocols thwarts attacks that previous QDB protocols were prone to; (4) and finally, our protocols also eliminate the need for communication from the prover to the verifier in the last authentication phase, which was necessary in some previous QDB protocols. Our work paves the way for several interesting research directions which we briefly discuss in detail in the appendix.

cs.CR↗

arXiv2022

Quantum Optimization Heuristics with an Application to Knapsack Problems

This paper introduces two techniques that make the standard Quantum Approximate Optimization Algorithm (QAOA) more suitable for constrained optimization problems. The first technique describes how to use the outcome of a prior greedy classical algorithm to define an initial quantum state and mixing operation to adjust the quantum optimization algorithm to explore the possible answers around this initial greedy solution. The second technique is used to nudge the quantum exploration to avoid the local minima around the greedy solutions. To analyze the benefits of these two techniques we run the quantum algorithm on known hard instances of the Knapsack Problem using unit depth quantum circuits. The results show that the adjusted quantum optimization heuristics typically perform better than various classical heuristics.

quant-ph↗

arXiv2021

F1: A Fast and Programmable Accelerator for Fully Homomorphic Encryption (Extended Version)

Fully Homomorphic Encryption (FHE) allows computing on encrypted data, enabling secure offloading of computation to untrusted serves. Though it provides ideal security, FHE is expensive when executed in software, 4 to 5 orders of magnitude slower than computing on unencrypted data. These overheads are a major barrier to FHE's widespread adoption. We present F1, the first FHE accelerator that is programmable, i.e., capable of executing full FHE programs. F1 builds on an in-depth architectural analysis of the characteristics of FHE computations that reveals acceleration opportunities. F1 is a wide-vector processor with novel functional units deeply specialized to FHE primitives, such as modular arithmetic, number-theoretic transforms, and structured permutations. This organization provides so much compute throughput that data movement becomes the bottleneck. Thus, F1 is primarily designed to minimize data movement. The F1 hardware provides an explicitly managed memory hierarchy and mechanisms to decouple data movement from execution. A novel compiler leverages these mechanisms to maximize reuse and schedule off-chip and on-chip data movement. We evaluate F1 using cycle-accurate simulations and RTL synthesis. F1 is the first system to accelerate complete FHE programs and outperforms state-of-the-art software implementations by gmean 5400x and by up to 17000x. These speedups counter most of FHE's overheads and enable new applications, like real-time private deep learning in the cloud.

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arXiv2021

Machine-checked ZKP for NP-relations: Formally Verified Security Proofs and Implementations of MPC-in-the-Head

MPC-in-the-Head (MitH) is a general framework that allows constructing efficient Zero Knowledge protocols for general NP-relations from secure multiparty computation (MPC) protocols. In this paper we give the first machine-checked implementation of this transformation. We begin with an EasyCrypt formalization of MitH that preserves the modular structure of MitH and can be instantiated with arbitrary MPC protocols that satisfy standard notions of security, which allows us to leverage an existing machine-checked secret-sharing-based MPC protocol development. The resulting concrete ZK protocol is proved secure and correct in EasyCrypt. Using a recently developed code extraction mechanism for EasyCrypt we synthesize a formally verified implementation of the protocol, which we benchmark to get an indication of the overhead associated with our formalization choices and code extraction mechanism.

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arXiv2020

Towards Automated Augmentation and Instrumentation of Legacy Cryptographic Executables: Extended Version

Implementation flaws in cryptographic libraries, design flaws in underlying cryptographic primitives, and weaknesses in protocols using both, can all lead to exploitable vulnerabilities in software. Manually fixing such issues is challenging and resource consuming, especially when maintaining legacy software that contains broken or outdated cryptography, and for which source code may not be available. While there is existing work on identifying cryptographic primitives (often in the context of malware analysis), none of this prior work has focused on replacing such primitives with stronger (or more secure ones) after they have been identified. This paper explores feasibility of designing and implementing a toolchain for Augmentation and Legacy-software Instrumentation of Cryptographic Executables (ALICE). The key features of ALICE are: (i) automatically detecting and extracting implementations of weak or broken cryptographic primitives from binaries without requiring source code or debugging symbols, (ii) identifying the context and scope in which such primitives are used, and performing program analysis to determine the effects of replacing such implementations with more secure ones, and (iii) replacing implementations of weak primitives with those of stronger or more secure ones. We demonstrate practical feasibility of our approach on cryptographic hash functions with several popular cryptographic libraries and real-world programs of various levels of complexity. Our experimental results show that ALICE can locate and replace insecure hash functions, even in large binaries (we tested ones of size up to 1.5MB), while preserving existing functionality of the original binaries, and while incurring minimal execution-time overhead in the rewritten binaries. We also open source ALICE's code at https://github.com/SRI-CSL/ALICE.

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arXiv2020

A Verified Architecture for Proofs of Execution on Remote Devices under Full Software Compromise

Modern society is increasingly surrounded by, and accustomed to, a wide range of Cyber-Physical Systems (CPS), Internet-of-Things (IoT), and smart devices. They often perform safety-critical functions, e.g., personal medical devices, automotive CPS and industrial automation (smart factories). Some devices are small, cheap and specialized sensors and/or actuators. They tend to run simple software and operate under control of a more sophisticated central control unit. The latter is responsible for the decision-making and orchestrating the entire system. If devices are left unprotected, consequences of forged sensor readings or ignored actuation commands can be catastrophic, particularly, in safety-critical settings. This prompts the following three questions: (1) How to trust data produced by a simple remote embedded device? and (2) How to ascertain that this data was produced via execution of expected software? Furthermore, (3) Is it possible to attain (1) and (2) under the assumption that all software on the remote device could be modified or compromised? In this paper we answer these questions by designing, proving security of, and formally verifying, VAPE: Verified Architecture for Proofs of Execution. To the best of our knowledge, this is the first of its kind result for low-end embedded systems. Our work has a range of applications, especially, to authenticated sensing and trustworthy actuation, which are increasingly relevant in the context of safety-critical systems. VAPE architecture is publicly available and our evaluation demonstrates that it incurs low overhead, affordable even for lowest-end embedded devices, e.g., those based on MSP430 or ARV ATMega processors.

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arXiv2019

Formally Verified Hardware/Software Co-Design for Remote Attestation

In this work, we take the first step towards formal verification of Remote Attestation (RA) by designing and verifying an architecture called VRASED: Verifiable Remote Attestation for Simple Embedded Devices. VRASED instantiates a hybrid (HW/SW) RA co-design aimed at low-end embedded systems, e.g., simple IoT devices. VRASED provides a level of security comparable to HW-based approaches, while relying on SW to minimize additional HW costs. Since security properties must be jointly guaranteed by HW and SW, verification is a challenging task, which has never been attempted before in the context of RA. We believe that VRASED is the first formally verified RA scheme. To the best of our knowledge, it is also the first formal verification of a HW/SW implementation of any security service. To demonstrate VRASED's practicality and low overhead, we instantiate and evaluate it on a commodity platform (TI MSP430). VRASED's publicly available implementation was deployed on the Basys3 FPGA.

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