Overview
- Quantus told reporters that recent quantum progress has tightened timelines for when machines could run Shor’s algorithm and threaten elliptic-curve signatures used by most blockchains.
- Google Quantum AI’s March 2026 paper is cited for estimating that attacking Bitcoin’s secp256k1 curve may require far fewer physical qubits than previously thought under certain hardware assumptions.
- Blockchains publish public keys permanently which lets attackers collect data today and decrypt accounts later, a risk the report describes as “harvest now, crack later.”
- Quantus estimated that roughly 2.3 million to 3.7 million Bitcoin are likely inaccessible because their private keys are lost, leaving those coins permanently exposed to future quantum attacks.
- Moving Bitcoin to post-quantum signatures faces steep hurdles because protocol changes need broad consensus, many hardware wallets lack memory for larger algorithms, and experts disagree between forced deadlines and staged hybrid migrations.