Hardy Index Quantum readiness, rated and tracked

Cryptography registry

Schnorr signatures on secp256k1

Schnorr signatures over the secp256k1 curve. Bitcoin's form is specified in BIP-340 and used by Taproot; Bitcoin Cash adopted its own Schnorr variant in 2019. Broken by Shor's algorithm on a cryptographically relevant quantum computer, which recovers the private key from the public key.

Quantum status
Broken by Shor's algorithm
Standard
BIP-340, final
Family
elliptic curve
Also known as
BIP-340, Schnorr

Rated chains using it

  • Bitcoin Mainnet, default

    Account signatures, BIP-340. Taproot outputs. Specification or proposal

  • Bitcoin Cash Mainnet, default

    Account signatures. Bitcoin Cash Schnorr, adopted in 2019; not BIP-340. Statement or write-up

  • Decred Mainnet, opt-in

    Account signatures, EC-Schnorr-DCRv0. Signature type 2, Decred's own Schnorr variant rather than BIP-340, verified by OP_CHECKSIGALT. Treasury spends must carry an EC-Schnorr-DCRv0 signature from one of the Politeia keys in the chain parameters (DCP-0006). Source code or release

  • eCash Mainnet, default

    Account signatures. The Schnorr variant activated in May 2019, before the split from Bitcoin Cash; not BIP-340. Specification or proposal

  • eCash Mainnet, mandatory

    Validator consensus. Avalanche proofs sign each stake with the staked coin's key, and delegations and poll responses carry 64-byte Schnorr signatures. Avalanche finalises blocks and, since November 2025, transactions. Specification or proposal

  • Internet Computer Mainnet, opt-in

    Threshold signing, BIP-340. Chain-key signatures. Specification or proposal

  • Kaspa Mainnet, default

    Account signatures, 32-byte x-coordinate keys. Address version 0 (PubKey). Source code or release

  • Midnight Mainnet, default

    Account signatures, BIP-340. Authorises unshielded UTXO spends on Midnight's ledger. Shielded spends use a zero-knowledge proof instead, and NIGHT held on Cardano as cNIGHT is under Cardano's Ed25519 keys. Specification or proposal

  • Qtum Mainnet, opt-in

    Account signatures. BIP-340 Schnorr for Taproot outputs, which the node verifies on every block; added in the v22.0 hard fork. Source code or release

Sources

Published beside the Hardy Score and not an input to it. How each chain is scored is set out in the methodology.