A cryptographically relevant quantum computer is one that is sufficiently powerful and error-tolerant to execute quantum algorithms (such as Shor’s algorithm) that can break widely used public key cryptography schemes. This means possessing enough logical qubits and quantum gates to threaten the digital signatures and encryption that secure blockchain systems, cryptocurrencies, and much of the internet.
Key Takeaways
- Cryptographically relevant means more than just a high qubit count - it requires demonstrated error correction and the ability to run long, complex quantum circuits with low failure rates.
- No such system exists today, but technology and research are progressing steadily.
What Makes a Quantum Computer Cryptographically Relevant?
It comes down to resource requirements: thousands of logical qubits, tens of millions of quantum gate operations, and robust error correction ensuring the overall algorithm succeeds in practice. The Google Quantum AI-led 2026 study estimates that attacking Bitcoin’s elliptic curve would need as many as 1,450 logical qubits and 70-90 million Toffoli gates, plus robust error correction and supporting infrastructure.
How Does This Compare to Today’s Machines?
Today’s best quantum computers operate with noisy, error-prone physical qubits and can only sustain modest program lengths. Gaps remain large, but closing, with governments and companies investing in hardware, error correction, and quantum software research.
Why Does This Matter for Post-Quantum Planning?
Knowing where the real boundaries are - rather than theoretical hype - ensures that organisations, individuals, and communities can plan responsible migrations and maintain sovereignty as technology changes.
Why This Matters to Tsuka
Assessing technological risk with an evidence-based mindset is core to Tsuka’s approach. Communicating what is and isn’t possible now, and what good stewardship requires, is central to fostering digital sovereignty and resilience.
About Tsuka
Tsuka provides research-driven insights to empower people navigating the future of technology, cryptography, and digital ownership - championing clear standards for verification and resilience.
Own Your Digital Life.
Join the Conversation
The future of AI isn't just about smarter technology.
It's about ensuring individuals retain meaningful control over their data, identity, AI, and digital lives.
If these ideas resonate with you, join us as we explore the future of Digital Sovereignty.
- 𝕏: @tsukaphilosophy
- Instagram: @tsukaphilosophy
- Telegram (Community): https://t.me/DejitaruTsukaSanghaOfficial
Own Your Digital Life. 🐉