The Hardy Index Quantum readiness benchmark

Guides

Quantum and crypto, explained plainly

The Hardy Index rates the chains. These guides answer the questions people actually ask about what that means for the coins they hold, in plain language and with every claim sourced.

Understand the threat

  • Is my crypto safe from quantum computers?

    Here is the reassuring part first: no quantum computer that could break the cryptography behind Bitcoin or Ethereum exists today, and the best public estimates put that machine years away. Most cryptocurrencies are not quantum-safe yet, though, and readiness varies widely between chains. The Hardy Index scores 23 major chains on exactly that.

  • Will quantum computers break Bitcoin?

    In theory, yes: a large enough quantum computer could break the cryptography securing Bitcoin, by deriving a private key from a public one. In practice, no such machine exists, and Bitcoin now has two draft proposals for defences. The Hardy Index rates Bitcoin 17.0 out of 100 on quantum readiness.

  • Q-Day: when will quantum computers break crypto?

    Q-Day is the day a quantum computer can break the cryptography protecting crypto and the wider internet. Nobody knows the date. Estimates quoted by Citi Institute put the chance before 2034 at 19% to 34%, rising to 60% to 82% by 2044, and those estimates keep moving.

  • Harvest now, decrypt later: what it means for your crypto

    Harvest now, decrypt later is the reason the quantum threat matters before Q-Day. An attacker records encrypted data or exposed public keys today, then breaks them once a quantum computer exists. For crypto, the concern is funds sitting at addresses whose public keys are already visible.

What to do about it

  • How to protect your crypto from quantum computers

    You cannot make an exposed chain quantum-safe yourself, but you can cut your risk today. Check how ready your chain is, stop reusing addresses, keep long-term holdings in a wallet whose keys you control, and take your chain's post-quantum upgrade when it ships. Here is the order to do it in.

  • Quantum-safe wallets: what is real and what is marketing

    A quantum-safe wallet is one whose signatures a quantum computer could not break. Very few exist, because a wallet can only use the signature scheme its blockchain accepts. The practical step today is a reputable hardware wallet plus good address habits, with genuinely post-quantum wallets still a small and emerging group.

  • Moving to a quantum-ready chain

    If you want to hold assets on a chain already built for the quantum era, a handful of layer-1s rate highest today. Moving means choosing a chain, using a compatible wallet, and transferring with care. The Hardy Index rates Quantum Resistant Ledger highest, at 92.0 out of 100, ahead of Abelian.

Which chains are ready

  • Which is the most quantum-resistant blockchain?

    As of 12 August 2026, the Hardy Index rates Quantum Resistant Ledger the most quantum-ready layer-1 blockchain, with a Hardy Score of 92.0 out of 100, ahead of Abelian on 84.5. Readiness is scored on signature scheme, deployment, NIST alignment, migration path, exposure and verification.

  • Which crypto is quantum proof?

    Very few. Most cryptocurrencies still use signatures a quantum computer could eventually break. As of 12 August 2026, the Hardy Index rates 2 of 23 major chains as post-quantum on mainnet today: Quantum Resistant Ledger and Abelian. Quantum proof is a spectrum rather than a badge.

This is a security-readiness assessment, not investment advice.