关键词: 密码体制识别, 序列密码算法, LDA降维算法, 全连接神经网络, 算法识别

Abstract: Based on the known ciphertext, cryptosystem identification is a process of identifying cryptographic algorithms by analyzing the potential feature information in ciphertext data. This paper presents a recognition scheme of sequential cryptosystem based on Hamming weight. This scheme generates labeled ciphertext feature vectors by calculating the Hamming weight of ciphertext blocks of different lengths. LDA dimensionality reduction technique is used to reduce the dimensionality of feature vectors, so as to optimize the extraction and utilization efficiency of data information. Finally, fully connected neural network is used to identify the feature vector after dimensionality reduction. The experimental results show that the proposed scheme can effectively perform two classification recognition experiments and eight classification recognition experiments on 8 stream cipher algorithms such as ZUC, Salsa20 and Decimv2, and achieve good recognition results. The average recognition rate of twoclass and eightclass recognition experiments is 99.29% and 79.12% respectively. Compared with the existing research, the accuracy of this scheme is improved by 16.29% compared with the existing literature with a small amount of ciphertext data.

Key words: cryptosystem recognition, stream cipher algorithm, linear discriminant analysis, fully connected neural networks, algorithm recognition