Quantus founder warns first quantum crypto attack will be silent

The first real attack by a quantum computer on cryptocurrency will probably look like a routine, unexplained breach rather than a dramatic takedown of a famous wallet, according to Quantus founder and cryptographer Dragos Ilie. He told CoinTelegraph that hackers with access to a working quantum machine will likely use it quietly to crack weak encryption and drain funds, not make a spectacle. The warning comes as researchers edge closer to building scalable quantum computers that could break widely used cryptographic schemes such as RSA and ECC, which underpin much of today’s blockchain security.

Quantum computing has moved from theory to lab milestones in the last five years. Google, IBM, and others now run quantum processors with over 400 qubits, though error rates and stability remain major hurdles. These machines won’t replace classical computers overnight, but they can already solve specific problems—like factoring large numbers—far faster than any classical supercomputer. That capability threatens the digital signatures and key exchanges that secure Bitcoin, Ethereum, and most other blockchains. Ilie said the first visible sign of a quantum attack might be a wallet drained of funds with no clear cause, making attribution nearly impossible until it’s too late.

Security firms have been racing to develop “quantum-resistant” cryptography. The U.S. National Institute of Standards and Technology (NIST) has been running a six-year standardization process for post-quantum algorithms, with final selections expected this year. Projects like Ethereum’s “Quantum Resistant Ledger” and Bitcoin Improvement Proposal 322 have also begun testing lattice-based signatures designed to withstand quantum attacks. Yet adoption remains patchy. Many older wallets, exchanges, and custody providers still rely on vulnerable encryption, creating a broad attack surface. Ilie warned that once a single quantum-capable entity cracks even a small fraction of these keys, the ripple effect could shake trust in the entire ecosystem.

What happens next could reshape crypto security overnight. If a major theft is traced to quantum decryption, expect an immediate scramble to upgrade software, replace keys, and overhaul custody models. Longer term, blockchains may need to implement quantum-safe consensus upgrades or hybrid signature schemes to stay ahead. The window to prepare is shrinking as quantum hardware improves, but most users and developers still aren’t racing against the clock. A quiet breach today could be the first warning that the crypto era is about to collide with the quantum one.