DSA Nonce Vulnerabilities: An Interactive Analysis
Cryptography and Security
Summary
The authors created an interactive tool to help people understand how the Digital Signature Algorithm (DSA) works, especially in cybersecurity contests called CTFs. Their platform not only shows how to sign and verify messages but also demonstrates common ways attackers exploit weak random numbers (nonces) to break signatures. It visually reveals each step and important values in the process, making it easier to follow than typical tools that only show inputs and outputs. Their tests confirmed the tool accurately models the signature process and three key attack methods.
Authors
Rundong Wei, Xiaomei Tian, Xiaoqi Li
Abstract
Digital signatures are fundamental to identity authentication and data integrity in cybersecurity, and the NIST-standardized Digital Signature Algorithm (DSA) frequently appears in the cryptography track of CTF competitions. However, DSA relies on number theory, modular arithmetic, and large-integer computation, making both the algorithm and its associated attacks difficult for beginners to follow. Conventional tools often expose only inputs and outputs, leaving the intermediate computations of signing, verification, and key-recovery attacks opaque. This paper presents a DSA signature analysis and visualisation platform tailored to CTF competitions. The platform provides three main capabilities: basic signature generation and verification, reproduction of common CTF attack methods, and dynamic visualisation of attack workflows. It covers three representative nonce vulnerabilities: nonce reuse, linear nonce leakage, and HNP-based lattice attacks. Stepwise displays and highlighted intermediate values make the underlying computations directly inspectable. Experiments show that the platform correctly reproduces the standard DSA workflow and all three attack scenarios.