What is it about?
Imagine giving someone permission to sign just one document on your behalf, with no possibility of reusing that permission. Classical systems can enforce such restrictions using shared ledgers, such as blockchains, or trusted authorities. However, these approaches require additional infrastructure and coordination, introducing overhead and potential vulnerabilities to manipulation. Quantum computing offers a fundamentally different possibility. Researchers have developed the concept of "one-shot signatures", in which a signing key is stored as a quantum state designed to be consumed after a single use. This makes it possible, in principle, to enforce single-use signing through the laws of quantum physics rather than relying on external recordkeeping. Importantly, the resulting signatures can be verified using ordinary computers, without requiring a quantum communication network. Building on earlier theoretical developments, our research presents a concrete quantum algorithm for one-shot signatures. We develop detailed quantum circuits for generating signing keys and signing messages, introduce a simplified approach for signing longer messages, and estimate the quantum computing resources required. Our work helps bridge the gap between theoretical cryptographic protocols and their potential realization on quantum computers, while identifying important security and implementation challenges that remain.
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Why is it important?
Quantum computing is often viewed as a threat to existing cryptographic systems, but it also offers opportunities to develop new forms of security that are not possible using classical computation alone. One-shot signatures are an example: they offer the possibility of enforcing single-use digital authorization through quantum physics, potentially reducing reliance on trusted authorities or shared ledgers and their associated overheads. Although the theoretical foundations of one-shot signatures have been established in previous research, translating these protocols into concrete quantum algorithms is an important step toward practical implementation. Our main contribution is to develop explicit quantum circuit constructions for the key operations involved in one-shot signatures. We introduce an efficient approach to generating the required quantum states, simplify the signing of multi-bit messages, and provide detailed estimates of the quantum resources needed. These results help clarify the computational requirements and identify opportunities for further optimization. By connecting theoretical cryptographic constructions with concrete quantum algorithms, this research provides a foundation for future developments in secure digital transactions, one-time authorization, and delegated signing. Important challenges, particularly those related to protecting the algorithms against attacks, remain before a fully secure practical implementation can be achieved.
Perspectives
What I find particularly interesting about quantum computing is its potential not only to challenge existing cryptographic systems but also to enable entirely new security capabilities. One-shot signatures are a fascinating example, where the unique properties of quantum mechanics offer possibilities that would otherwise require additional infrastructure and coordination in classical systems. While the theoretical foundations of one-shot signatures have been developed in earlier research, translating these ideas into concrete quantum algorithms presents its own challenges. This was the main motivation behind our work. Together with colleagues at BTQ Technologies and QPerfect, we focused on developing explicit quantum circuits for the key operations, simplifying the process of signing longer messages, and understanding the quantum computing resources required. For me, an important aspect of this research is bridging the gap between theoretical cryptographic constructions and their algorithmic realization. Although significant challenges remain, particularly in achieving a fully secure implementation, I hope our work provides a useful foundation for further research and brings these ideas closer to practical quantum technologies.
Gopikrishnan Muraleedharan
BTQ Technologies Corp.
Read the Original
This page is a summary of: A quantum algorithm for one-shot signatures, November 2026, ACM (Association for Computing Machinery),
DOI: 10.1145/3839338.3857255.
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