A New Security Enhancing Solution when Building Digital Signature Schemes
Received: 29 January 2025 | Revised: 25 February 2025 | Accepted: 7 March 2025 | Online: 4 June 2025
Corresponding author: Ha Nguyen Hoang
Abstract
This article introduces a new solution to enhance the security of the digital signature system. First, a new type of hard problem is proposed, which is then used to construct a digital signature scheme. The core difficulty lies in the Discrete Logarithm Problem (DLP) modulo, a composite number which extends the DLP over a finite field by replacing the prime modulus with a composite one. This change leads to a digital signature scheme built on the DLP modulo, a composite number having the same level of security as the schemes constructed simultaneously on two hard problems: the DLP and the Integer Factorization Problem (IFP). This can be seen as a new direction in using two hard problems concurrently to construct a digital signature scheme. The current study also demonstrates that the digital signature scheme built upon a newly proposed problem, achieves a higher security level of 128 bits while minimizing the signature size to 512 bits. That is, although the schemes are built on a single hard problem, a possible attacker must solve two hard problems simultaneously in order to break them. Furthermore, the proposed hard problem can be used to construct both single-signer and multi-signer digital signature schemes, demonstrating the security and applicability of the new hard problem, introduced in this paper.
Keywords:
prime modulus, composite modulus, Schnorr’s digital signature, collective digital signatureDownloads
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Copyright (c) 2025 Kim Tuan Nguyen, Ha Nguyen Hoang, Duy Ho Ngoc

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