Overview
- Grayscale urged public blockchains to start post‑quantum planning now after Google estimated 1,200–1,450 logical qubits could break today’s signatures.
- Risk differs by design, with Ethereum flagged for multiple attack paths and Bitcoin seen as less exposed because it uses a UTXO model, proof‑of‑work, and no native smart contracts.
- The research highlights a short on‑spend window when a transaction reveals a public key, and reporting notes about 6.9 million BTC already have public keys exposed on‑chain.
- Post‑quantum tools exist today, with XRPL testing ML‑DSA signatures on its AlphaNet and using key rotation for upgrades, while Solana is running related trials.
- Next steps hinge on coordination, as Adam Back urges a long migration window for users to move their keys and Samson Mow warns current schemes enlarge signatures and could slow networks.