Cryptography

21 pages, 360 KiB

Open AccessArticle

Efficient Secure Multi-Party Computation for Multi-Dimensional Arithmetics and Its Applications

by Dongyu Wu, Bei Liang, Zijie Lu and Jintai Ding

Cryptography 2025, 9(3), 50; https://doi.org/10.3390/cryptography9030050 - 3 Jul 2025

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Over years of development in secure multi-party computation (MPC), many sophisticated functionalities have been made practical, and multi-dimensional operations occur more and more frequently in MPC protocols, especially in protocols involving datasets of vector elements, such as privacy-preserving biometric identification and privacy-preserving machine learning. In this paper, we introduce a new kind of correlation, called tensor triples, which is designed to make multi-dimensional MPC protocols more efficient. We will discuss the generation process, the usage, and the applications of tensor triples and show that they can accelerate privacy-preserving biometric identification protocols, such as FingerCode, Eigenfaces, and FaceNet, by more than 1000 times, with reasonable offline costs, and grant pre-computability for the secure matrix multiplication process in privacy-preserving machine learning protocols, such as SecureML and SecureNN, while achieving similar efficiency. Full article

(This article belongs to the Special Issue Cryptography and Network Security—CANS 2024)

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25 pages, 7476 KiB

Open AccessArticle

Image Encryption with Dual Watermark Based on Chaotic Map

by Ran Chu, Jun Mou and Yuanhui Cui

Cryptography 2025, 9(3), 49; https://doi.org/10.3390/cryptography9030049 - 1 Jul 2025

Viewed by 385

Abstract

A dual watermark and DNA image encryption based on a chaotic map is proposed. Firstly, a new discrete chaotic map is proposed, and the dynamic characteristics are analyzed. Then, the hash value changes initial conditions, and the pseudo-random sequence is generated. The encrypted copyright image is fused with the feature value of the original image and then encrypted again to form zero-watermarking, which is registered with the copyright certification authority. The zero-watermarking is taken as a robust watermark and embedded into the original image based on a chaotic sequence to ensure its invisibility. Finally, a cross-mutation DNA encryption is proposed. The experimental results verify the performance of encryption and dual watermark copyright authentication, and the ability to resist attacks. Full article

(This article belongs to the Special Issue Advanced Techniques in Watermarking, Encryption and Steganography for Secure Communication)

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31 pages, 1262 KiB

Open AccessArticle

Composable Privacy-Preserving Framework for Stakes-Based Online Peer-to-Peer Applications

by Nikola Hristov-Kalamov, Raúl Fernández-Ruiz, Agustín Álvarez-Marquina, Julio Guillén-García, Roberto Gallardo-Cava and Daniel Palacios-Alonso

Cryptography 2025, 9(3), 48; https://doi.org/10.3390/cryptography9030048 - 1 Jul 2025

Viewed by 134

Abstract

As the demand for expansive back-end systems in online applications continues to grow, novel frameworks are necessitated to address the escalating operational demands, energy consumption, and associated costs. Traditional Client–Server models, while offering centralized security and reliability, are characterized by their high deployment and maintenance expenses. Conversely, Peer-to-Peer (P2P) models, despite being cost-effective and scalable, are hindered by inherent security and data integrity challenges. Moreover, the lack of a central authority in P2P systems complicates a definitive resolution of scenarios involving stakes, where users cannot withdraw without incurring a tangible loss. In this research work, a hybrid back-end framework is introduced, combining the advantages of both models through the utilization of cryptographic algorithms and Secure Multi-Party Computation (MPC) protocols. The baseline solution is lightweight and fully composable, making it capable of utilizing different more complex slot-in MPC techniques. The proposed framework’s effectiveness is demonstrated through a simplified two-player Spades game, although it is fully generalizable to any application. Evaluations across multiple case studies reveal substantial performance enhancements compared to conventional approaches, particularly post-initialization, highlighting the scheme’s potential as a cost-effective, energy-efficient, and secure solution for modern online applications. Full article

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26 pages, 784 KiB

Open AccessArticle

The Eye-Opening Arbiter-PUF FPGA Implementation with Auto Error Detection

by Holger Mandry, Julian Spiess, Bjoern Driemeyer, Joachim Becker and Maurits Ortmanns

Cryptography 2025, 9(3), 47; https://doi.org/10.3390/cryptography9030047 - 1 Jul 2025

Viewed by 163

Abstract

We present the first implementation of an FPGA-based PUF that leverages the usually contradictory requirements of stability and response time. Many state-of-the-art implementations of PUFs are either slow with a low error rate, like the ring oscillator-PUF, or fast with a higher error rate, like the arbiter-PUF. The presented implementation of an eye-opening PUF uses the phase-integrating effect of a ring oscillator to realize the shortest possible response for the required stability of the readout. This principle also allows for new automatic detection of unstable bits based on counting the number of oscillations required until an arbitration is conducted. This first implementation of an eye-opening PUF reduces the bit error rate to a number under our measurement limits, while the readout time is simultaneously kept as low as ≤1.54 μs, with an average of 0.85 μs. In addition, environmental temperature changes are evaluated, and methods for limiting these effects are discussed. Full article

(This article belongs to the Special Issue Emerging Topics in Hardware Security)

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Cryptography, Volume 9, Issue 3 (September 2025) – 4 articles

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