arXiv subjects

Yongge Wang

Publications and source records attributed to Yongge Wang.

At least 19 recordsLinked to original sources

arXiv2026

High-Dimensional Carrier-Assisted Entanglement Purification Based on Mutually Unbiased Bases

Distilling high-dimensional entanglement under general asymmetric Pauli noise remains challenging. For the unprocessed qutrit single-carrier recurrence studied here, severe noise asymmetry can prevent the convergence condition from being satisfied. In this paper, we investigate carrier-assisted entanglement purification protocols, namely CAEPP and mCAEPP, first for two-qutrit systems, and show that the unprocessed single-carrier recurrence is bottlenecked by marginal $X$-error probabilities. To overcome this limitation, we introduce MUB-guided preprocessing that combines randomized inversion-pair symmetrization with deterministic maximum-line alignment. For any qutrit Pauli channel with initial fidelity $p_{00}>1/3$, we prove that, conditioned on successful syndrome outcomes, the MUB-adapted recurrence converges for every sufficiently large fixed carrier number and that its fixed-point fidelity approaches one in the subsequent large-carrier limit. We further extend the algebraic carrier-assisted framework and the asymmetric-noise bottleneck to arbitrary qudit dimensions, and show that in prime-power dimensions the finite-field preprocessing gives the sufficient threshold $p_{00}>1/d$. A certified equal-target comparison over a finite deterministic optimization domain further shows that neither the MUB-adapted strategy nor complete Pauli-label twirling uniformly dominates the other in finite-resource cost.

quant-ph↗

arXiv2026

Spatiotemporal Co-reflection with Spacetime Discontinuities at Moving Interfaces

The control of reflection and refraction at interfaces using engineered media is central to numerous optical technologies, with negative refraction and the suppression of backscattering representing two prominent research frontiers. In this work, we demonstrate that an effective negative refraction accompanied by an absence of backscattering can be realized at a moving spatiotemporal interface when temporal and spatial reflections occur concurrently. While such spatiotemporal co-reflection is prohibited in one-dimensional linear dispersive media, we show that it becomes permissible under oblique incidence within a specific range of traveling-wave modulation velocities. Leveraging this mechanism, we propose a spatiotemporal flat lens capable of nonreciprocal electromagnetic wave focusing. These findings provide a framework for developing advanced spatiotemporal metamaterials and time-varying metasurfaces.

physics.optics↗

arXiv2026

Breaking the Limitations of Temporal Modulation via Mixed Continuity Conditions

The conventional description of time-varying media assumes that electromagnetic fields evolve according to fixed continuity conditions during parameter jumps. Here we reveal that these conditions are not physical constraints but tunable design degrees of freedom. By developing a unified framework that treats continuity rules as engineerable parameters, we expand the scope of time-varying metamaterials and enable wave phenomena previously considered impossible. For instance, non-resonant, reflectionless wave amplification without momentum bandgaps, and reversible conversion between propagating waves and static fields for optical memory, etc. This work opens a new dimension for controlling light-matter interactions.

physics.optics↗

arXiv2025

Entanglement distillation on symmetric two-qutrit entangled states of rank five

Entanglement distillation is a key step in quantum information, both theoretically and practically. It has been proven that non-positive-partial transpose (NPT) entangled states of rank at most four is 1-distillable under local operation and classical communications. In this paper we investigate the distillation of a more complex family of NPT entangled states, namely a family of symmetric two-qutrit states $\r$ of rank five with given eigenvectors. We explicitly construct five families of such states by requiring four of the five eigenvalues to be the same. We respectively show that some of them are 1-distillable. It turns out that such states may be not 1-distillable for some interval of eigenvalues. We provide some conditions for eigenvalues that allow $\r$ to be 1-distillable or to be 1-undistillable.

quant-ph↗

arXiv2024

Automated Market Makers for Decentralized Finance (DeFi)

This paper compares mathematical models for automated market makers including logarithmic market scoring rule (LMSR), liquidity sensitive LMSR (LS-LMSR), constant product/mean/sum, and others. It is shown that though LMSR may not be a good model for Decentralized Finance (DeFi) applications, LS-LMSR has several advantages over constant product/mean based automated market makers. However, LS-LMSR requires complicated computation (i.e., logarithm and exponentiation) and the cost function curve is concave. In certain DeFi applications, it is preferred to have computationally efficient cost functions with convex curves to conform with the principle of supply and demand. This paper proposes and analyzes constant circle/ellipse based cost functions for automated market makers. The proposed cost functions are computationally efficient (only requires multiplication and square root calculation) and have several advantages over widely deployed constant product cost functions. For example, the proposed market makers are more robust against front-runner (slippage) attacks.

q-fin.TR↗

arXiv2021

Implementing Automated Market Makers with Constant Circle

This paper describe the implementation details of constant ellipse based automated market makers (CoinSwap). A CoinSwap prototype has been implemented at http://coinswapapp.io/ and the source codes are available at https://github.com/coinswapapp/

cs.CR↗

arXiv2020

Blockchain BFT Protocol for Complete Asynchronous Networks

Ethereum Research team has proposed a family of Casper blockchain consensus protocols for Ethereum 2.0. It has been shown in the literature that Casper Friendly Finality Gadget (Casper FFG) for Ethereum 2.0's beacon network cannot achieve liveness property in partially synchronous networks such as the Internet environment. The "Correct-by-Construction" family of Casper blockchain consensus protocols (CBC Casper) has been proposed as a finality gadget for the future release of Ethereum 2.0 blockchain. Unfortunately, neither constructive finality rule nor satisfactory liveness property has been obtained for CBC Casper, and it is commonly believed that CBC Casper could not achieve liveness property in asynchronous networks. This paper provides the first probabilistic CBC Casper protocol that achieves liveness property against (n-1)/3 Byzantine participants in complete asynchronous networks.

cs.CR↗

arXiv2020

Another Look at ALGORAND

ALGORAND is a celebrated public ledger technology. In this paper, we identify several design flaws of the ALGORAND protocol. In particular, we show that the claimed (proved) fork-free property is not true and several assumptions in ALGORAND are not realistic in practice. The ALGORAND wiki page https://golden.com/wiki/Algorand claims that "the probability of a fork in the protocol is estimated at 1/1,000,000,000 and therefore blocks can be considered final upon validation". However, our first attack in this paper shows that a malicious adversary who controls less than 1/3 of the users (or money units) could fork the ALGORAND chain very easily. Our second attack shows that a malicious adversary could use a bribery attack to fork the ALGORAND chain very easily also. Furthermore, we show that the celebrated Byzantine Agreement component in ALGORAND is not necessary. The Byzantine Agreement is the most expensive part and one of the most innovative parts in the ALGORAND protocol. It is used to avoid forks in ALGORAND. We show that a simple majority vote could be used to achieve the same property that Byzantine Agreement achieves in ALGORAND under the same network assumption.

cs.CR↗

arXiv2019

Octonion Algebra and Noise-Free Fully Homomorphic Encryption (FHE) Schemes

Brakerski showed that linearly decryptable fully homomorphic encryption (FHE) schemes cannot be secure in the chosen plaintext attack (CPA) model. In this paper, we show that linearly decryptable FHE schemes cannot be secure even in the ciphertext only security model. Then we consider the maximum security that a linearly decryptable FHE scheme could achieve. This paper designs fully homomorphic symmetric key encryption (FHE) schemes without bootstrapping (that is, noise-free FHE schemes). The proposed FHE schemes are based on quaternion/octonion algebra and Jordan algebra over finite rings Z_n and are secure in the weak ciphertext-only security model assuming the hardness of solving multivariate quadratic equation systems and solving univariate high degree polynomial equation systems in Z_n. It is up to our knowledge that this is the first noise-free FHE scheme that has ever been designed with a security proof (even in the weak ciphertext-only security model). It is argued that the weak ciphertext-only security model is sufficient for various applications such as privacy preserving computation in cloud. As an example, the proposed FHE schemes are used to construct obfuscated programs. This example could be further used to show that the scheme presented in this paper could be combined with existing FHE schemes with bootstrapping to obtain more efficient FHE schemes with bootstrapping in the fully CPA model. At the end of the paper, we point out the insecurity of several recently proposed noise-free FHE schemes.

cs.CR↗

arXiv2017

Decoding Generalized Reed-Solomon Codes and Its Application to RLCE Encryption Schemes

This paper compares the efficiency of various algorithms for implementing quantum resistant public key encryption scheme RLCE on 64-bit CPUs. By optimizing various algorithms for polynomial and matrix operations over finite fields, we obtained several interesting (or even surprising) results. For example, it is well known (e.g., Moenck 1976 \cite{moenck1976practical}) that Karatsuba's algorithm outperforms classical polynomial multiplication algorithm from the degree 15 and above (practically, Karatsuba's algorithm only outperforms classical polynomial multiplication algorithm from the degree 35 and above ). Our experiments show that 64-bit optimized Karatsuba's algorithm will only outperform 64-bit optimized classical polynomial multiplication algorithm for polynomials of degree 115 and above over finite field $GF(2^{10})$. The second interesting (surprising) result shows that 64-bit optimized Chien's search algorithm ourperforms all other 64-bit optimized polynomial root finding algorithms such as BTA and FFT for polynomials of all degrees over finite field $GF(2^{10})$. The third interesting (surprising) result shows that 64-bit optimized Strassen matrix multiplication algorithm only outperforms 64-bit optimized classical matrix multiplication algorithm for matrices of dimension 750 and above over finite field $GF(2^{10})$. It should be noted that existing literatures and practices recommend Strassen matrix multiplication algorithm for matrices of dimension 40 and above. All our experiments are done on a 64-bit MacBook Pro with i7 CPU and single thread C codes. It should be noted that the reported results should be appliable to 64 or larger bits CPU architectures. For 32 or smaller bits CPUs, these results may not be applicable. The source code and library for the algorithms covered in this paper are available at http://quantumca.org/.

cs.IT↗

arXiv2015

Quantum Resistant Random Linear Code Based Public Key Encryption Scheme RLCE

Lattice based encryption schemes and linear code based encryption schemes have received extensive attention in recent years since they have been considered as post-quantum candidate encryption schemes. Though LLL reduction algorithm has been one of the major cryptanalysis techniques for lattice based cryptographic systems, key recovery cryptanalysis techniques for linear code based cryptographic systems are generally scheme specific. In recent years, several important techniques such as Sidelnikov-Shestakov attack, filtration attacks, and algebraic attacks have been developed to crypt-analyze linear code based encryption schemes. Though most of these cryptanalysis techniques are relatively new, they prove to be very powerful and many systems have been broken using them. Thus it is important to design linear code based cryptographic systems that are immune against these attacks. This paper proposes linear code based encryption scheme RLCE which shares many characteristics with random linear codes. Our analysis shows that the scheme RLCE is secure against existing attacks and we hope that the security of the RLCE scheme is equivalent to the hardness of decoding random linear codes. Example parameters for different security levels are recommended for the scheme RLCE.

cs.CR↗

arXiv2014

On the Design of LIL Tests for (Pseudo) Random Generators and Some Experimental Results

NIST SP800-22 (2010) proposes the state of art testing suite for (pseudo) random generators to detect deviations of a binary sequence from randomness. On the one hand, as a counter example to NIST SP800-22 test suite, it is easy to construct functions that are considered as GOOD pseudorandom generators by NIST SP800-22 test suite though the output of these functions are easily distinguishable from the uniform distribution. Thus these functions are not pseudorandom generators by definition. On the other hand, NIST SP800-22 does not cover some of the important laws for randomness. Two fundamental limit theorems about random binary strings are the central limit theorem and the law of the iterated logarithm (LIL). Several frequency related tests in NIST SP800-22 cover the central limit theorem while no NIST SP800-22 test covers LIL. This paper proposes techniques to address the above challenges that NIST SP800-22 testing suite faces. Firstly, we propose statistical distance based testing techniques for (pseudo) random generators to reduce the above mentioned Type II errors in NIST SP800-22 test suite. Secondly, we propose LIL based statistical testing techniques, calculate the probabilities, and carry out experimental tests on widely used pseudorandom generators by generating around 30TB of pseudorandom sequences. The experimental results show that for a sample size of 1000 sequences (2TB), the statistical distance between the generated sequences and the uniform distribution is around 0.07 (with $0$ for statistically indistinguishable and $1$ for completely distinguishable) and the root-mean-square deviation is around 0.005.

cs.CR↗

arXiv2012

sSCADA: Securing SCADA Infrastructure Communications

Distributed control systems (DCS) and supervisory control and data acquisition (SCADA) systems were developed to reduce labour costs, and to allow system-wide monitoring and remote control from a central location. Control systems are widely used in critical infrastructures such as electric grid, natural gas, water and wastewater industries. While control systems can be vulnerable to a variety of types of cyber attacks that could have devastating consequences, little research has been done to secure the control systems. American Gas Association (AGA), IEC TC57 WG15, IEEE, NIST and National SCADA Test Bed Program have been actively designing cryptographic standard to protect SCADA systems. American Gas Association (AGA) had originally been designing cryptographic standard to protect SCADA communication links and finished the report AGA 12 part 1. The AGA 12 part 2 has been transferred to IEEE P1711. This paper presents an attack on the protocols in the first draft of AGA standard (Wright et al., 2004). This attack shows that the security mechanisms in the first version of the AGA standard protocol could be easily defeated. We then propose a suite of security protocols optimised for SCADA/DCS systems which include: point-to-point secure channels, authenticated broadcast channels, authenticated emergency channels, and revised authenticated emergency channels. These protocols are designed to address the specific challenges that SCADA systems have.

cs.IT↗

arXiv2012

Efficient Identity-Based and Authenticated Key Agreement Protocol

Several identity based and implicitly authenticated key agreement protocols have been proposed in recent years and none of them has achieved all required security properties. In this paper, we propose an efficient identity-based and authenticated key agreement protocol IDAK using Weil/Tate pairing. The security of IDAK is proved in Bellare-Rogaway model. Several required properties for key agreement protocols are not implied by the Bellare-Rogaway model. We proved these properties for IDAK separately.

cs.CR↗

arXiv2012

Edge-Colored Graphs with Applications To Homogeneous Faults

In this paper, we use the concept of colored edge graphs to model homogeneous faults in networks. We then use this model to study the minimum connectivity (and design) requirements of networks for being robust against homogeneous faults within certain thresholds. In particular, necessary and sufficient conditions for most interesting cases are obtained. For example, we will study the following cases: (1) the number of colors (or the number of non-homogeneous network device types) is one more than the homogeneous fault threshold; (2) there is only one homogeneous fault (i.e., only one color could fail); and (3) the number of non-homogeneous network device types is less than five.

cs.DM↗

arXiv2012

Using mobile agent results to create hard-to-detect computer viruses

The theory of computer viruses has been studied by several authors, though there is no systematic theoretical study up to now. The long time open question in this area is as follows: Is it possible to design a signature-free (including dynamic signatures which we will define late) virus? In this paper, we give an affirmative answer to this question from a theoretical viewpoint. We will introduce a new stronger concept: dynamic signatures of viruses, and present a method to design viruses which are static signature-free and whose dynamic signatures are hard to determine unless some cryptographic assumption fails. We should remark that our results are only for theoretical interest and may be resource intensive in practice.

cs.CR↗

arXiv2012

Public Key Cryptography Standards: PKCS

Cryptographic standards serve two important goals: making different implementations interoperable and avoiding various known pitfalls in commonly used schemes. This chapter discusses Public-Key Cryptography Standards (PKCS) which have significant impact on the use of public key cryptography in practice. PKCS standards are a set of standards, called PKCS #1 through #15. These standards cover RSA encryption, RSA signature, password-based encryption, cryptographic message syntax, private-key information syntax, selected object classes and attribute types, certification request syntax, cryptographic token interface, personal information exchange syntax, and cryptographic token information syntax. The PKCS standards are published by RSA Laboratories. Though RSA Laboratories solicits public opinions and advice for PKCS standards, RSA Laboratories retain sole decision-making authority on all aspects of PKCS standards. PKCS has been the basis for many other standards such as S/MIME.

cs.CR↗

arXiv2012

Approximate Inverse Frequent Itemset Mining: Privacy, Complexity, and Approximation

In order to generate synthetic basket data sets for better benchmark testing, it is important to integrate characteristics from real-life databases into the synthetic basket data sets. The characteristics that could be used for this purpose include the frequent itemsets and association rules. The problem of generating synthetic basket data sets from frequent itemsets is generally referred to as inverse frequent itemset mining. In this paper, we show that the problem of approximate inverse frequent itemset mining is {\bf NP}-complete. Then we propose and analyze an approximate algorithm for approximate inverse frequent itemset mining, and discuss privacy issues related to the synthetic basket data set. In particular, we propose an approximate algorithm to determine the privacy leakage in a synthetic basket data set.

cs.DB↗