In the proposed signature model, the quantum private key collapses when signing and cannot be reused.
The implementation of the model on real hardware is planned for mid-2027
BTQ Technologies spoke this June 9, through its BTQ Insider series, about the so-called One-Shot Signatures (OSS): A digital signature scheme in which the private key exists as a quantum state and is destroyed at the time of signing.
The demonstration of the project that is in full development, and its implications for protecting Bitcoin, was led by Gavin Brennen, scientific director of the firm, and Chris Tam, former president of BTQ. Both explain that the principle of quantum non-cloning makes it the private key cannot be copied or reused: When signing a message, the quantum state collapses irreversibly.
The signature is verifiable by anyone with the corresponding public key, but the act of signing destroys the ability to do it again. The company notes that this solves a problem that no classical scheme can guarantee with certainty: that an authorization occurs only once.
BTQ is a quantum technology company listed on Nasdaq (BTQ) and CBOE Canada, founded by cryptographers specializing in post-quantum security. Its relevance This is because it develops both hardware and software aimed at protecting critical networks. before the arrival of quantum computers at scale. Brennen is also a Professor of Physics at Macquarie University in Sydney, with more than 20 years of experience in the field.
The initiative is part of an active debate within the ecosystem regarding the possible arrival of Q-Day. CriptoNoticias reported that Google Quantum AI researchers determined that a quantum computer with millions of qubits could breach Bitcoin’s elliptic curve cryptography in the time it takes to mine a block.
In this line of action, Israeli mathematician Gil Kalai maintains that quantum error correction is ineffective at scale, which would make this type of attack unfeasible. The debate on the actual deadlines is still open.
The new signature scheme and its applications in Bitcoin
The BTQ proposal part of the vulnerability that quantum computing represents for security signatures ECDSA elliptic curvethe digital signature system that protects Bitcoin transactions. If an actor with sufficient quantum capability were to access a public key exposed on the chain, they could derive the private key and move the owner’s funds without their consent.
One-Shot Signatures seek to neutralize this vector: as they are destroyed after each use, there is no recoverable or reusable private key. According to the firm, the use cases go beyond Bitcoin and include:
- Interbank transactions that must occur only once
- Single-use authorization tokens
- Release of medical records with single access traceability
BTQ points out that the implementation requires specialized quantum hardwareeither. The firm plans to complete its Quantum Logic Unit (QLU) in version 1 around mid-2027, through its subsidiary QPerfect, as a preliminary step to running OSS on real neutral atom platforms.
Brennen He maintained during the interview that this path integrates ideas from quantum computing and classical cryptography in a way that does not require a quantum internet to function: just one-time access to quantum devices at the time of signing is sufficient.