The K-nearest neighbor (KNN) algorithm is one of the most extensively used classification algorithms, while its high time complexity limits its performance in the era of big data. The quantum K-nearest neighbor (QKNN) algorithm can handle the above problem with satisfactory efficiency; however, its accuracy is sacrificed when directly applying the traditional similarity measure based on Euclidean distance. Inspired by the Polar coordinate system and the quantum property, this work proposes a new similarity measure to replace the Euclidean distance, which is defined as Polar distance. Polar distance considers both angular and module length information, introducing a weight parameter adjusted to the specific application data. To validate the efficiency of Polar distance, we conducted various experiments using several typical datasets. For the conventional KNN algorithm, the accuracy performance is comparable when using Polar distance for similarity measurement, while for the QKNN algorithm, it significantly outperforms the Euclidean distance in terms of classification accuracy. Furthermore, the Polar distance shows scalability and robustness superior to the Euclidean distance, providing an opportunity for the large-scale application of QKNN in practice.

Binary code similarity detection is used to calculate the code similarity of a pair of binary functions or files, through a certain calculation method and judgment method. It is a fundamental task in the field of computer binary security. Traditional methods of similarity detection usually use graph matching algorithms, but these methods have poor performance and unsatisfactory effects. Recently, graph neural networks have become an effective method for analyzing graph embeddings in natural language processing. Although these methods are effective, the existing methods still do not sufficiently learn the information of the binary code. To solve this problem, we propose Codeformer, an iterative model of a graph neural network (GNN)-nested Transformer. The model uses a Transformer to obtain an embedding vector of the basic block and uses the GNN to update the embedding vector of each basic block of the control flow graph (CFG). Codeformer iteratively executes basic block embedding to learn abundant global information and finally uses the GNN to aggregate all the basic blocks of a function. We conducted experiments on the OpenSSL, Clamav and Curl datasets. The evaluation results show that our method outperforms the state-of-the-art models.

Support vector machine(SVM) is one of the most popular machine learning(ML) methods which are widely used as the methodology of choice in Breast Cancer detection because of its unique advantages in critical features detection from complex breast cancer datasets. Quantum support vector machine(QSVM) uses the power of quantum mechanics to improve the performance of classical support vector machine(SVM) algorithms with theoretical acceleration advantage. However, it still suffers from the wide error problem and hardware limits in Noisy Intermediate-Scale Quantum computing(NISQ). Consequently, we propose a quantum kernel estimation method with measurement error mitigation and test it using the Wisconsin Breast Cancer database first on the IBM quantum processors. The experimental results show that we can achieve remarkable performance improvement in accuracy for solving such binary classification problems compared to state-of-the-art models, which shows the great potential for the design and implementation of machine learning algorithms with quantum advantages in the future.

In the field of network security, although there has been related work on software vulnerability detection based on classic machine learning, detection ability is directly proportional to the scale of training data. A quantum neural network has been proven to solve the memory bottleneck problem of classical machine learning, so it has far-reaching prospects in the field of vulnerability detection. To fill the gap in this field, we propose a quantum neural network structure named QDENN for software vulnerability detection. This work is the first attempt to implement word embedding of vulnerability codes based on a quantum neural network, which proves the feasibility of a quantum neural network in the field of vulnerability detection. Experiments demonstrate that our proposed QDENN can effectively solve the inconsistent input length problem of quantum neural networks and the problem of batch processing with long sentences. Furthermore, it can give full play to the advantages of quantum computing and realize a vulnerability detection model at the cost of a small amount of measurement. Compared to other quantum neural networks, our proposed QDENN can achieve higher vulnerability detection accuracy. On the sub dataset with a small-scale interval, the model accuracy rate reaches 99%. On each subinterval data, the best average vulnerability detection accuracy of the model reaches 86.3%.

In recent years, the number of smart contracts running in the blockchain has increased rapidly, accompanied by many security problems, such as vulnerability propagation caused by code reuse or vicious transaction caused by malicious contract deployment, for example. Most smart contracts do not publish the source code, but only the bytecode. Based on the research of bytecode similarity of smart contract, smart contract upgrade, vulnerability search and malicious contract analysis can be carried out. The difficulty of bytecode similarity research is that different compilation versions and optimization options lead to the diversification of bytecode of the same source code. This paper presents a solution, including a series of methods to measure the similarity of smart contract bytecode. Starting from the opcode of smart contract, a method of pre-training the basic block sequence of smart contract is proposed, which can embed the basic block vector. Positive samples were obtained by basic block marking, and the negative sampling method is improved. After these works, we put the obtained positive samples, negative samples and basic blocks themselves into the triplet network composed of transformers. Our solution can obtain evaluation results with an accuracy of 97.8%, so that the basic block sequence of optimized and unoptimized options can be transformed into each other. At the same time, the instructions are normalized, and the order of compiled version instructions is normalized. Experiments show that our solution can effectively reduce the bytecode difference caused by optimization options and compiler version, and improve the accuracy by 1.4% compared with the existing work. We provide a data set covering 64 currently used Solidity compilers, including one million basic block pairs extracted from them.

Nowadays, the time lag between vulnerability discovery and the timely remediation of the vulnerability is extremely important to the current state of cybersecurity. Unfortunately, the silent security patch presents a significant challenge. Despite related work having been conducted in this area, the patch identification lacks interpretability. To solve this problem, this paper first proposes a trusted multi-view security patch identification system called TMVDPatch. The system obtains evidence from message commit and code diff views respectively, and models the uncertainty of each view based on the D-S evidence theory, thereby providing credible and interpretable security patch identification results. On this basis, this paper performs weighted training on the original evidence based on the grey relational analysis method to improve the ability to make credible decisions based on multi-views. Experimental results show that the multi-view learning method exhibits excellent capabilities in terms of the complementary information provided by control dependency and data dependency, and the model shows strong robustness across different hyperparameter settings. TMVDPatch outperforms other models in all evaluation metrics, achieving an accuracy of 85.29% and a F1 score of 0.9001, clearly verifying the superiority of TMVDPatch in terms of accuracy, scientificity, and reliability.