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Schnorr signature

BIP 340 specifies fixed 64-byte Schnorr signatures over secp256k1 for Bitcoin Taproot spends. Linearity enables key and signature aggregation protocols, while tagged hashes and x-only 32-byte public keys fix Bitcoin’s encoding.

Bitcoin Schnorr signatures are the fixed 64-byte BIP340 signature scheme over secp256k1 used by Taproot and designed with deterministic verification and safe aggregation properties.

BIP340 uses x-only public keys and tagged hashes to bind protocol contexts. [BIP 340 — Schnorr Signatures] [BIP 341 — Taproot]

Linearity enables multisignature constructions such as MuSig2 but does not make naive signature addition safe. [BIP 340 — Schnorr Signatures] [Bitcoin Optech — Schnorr signatures]

Legacy and SegWit v0 inputs still use ECDSA; activation did not replace every historical signature rule. [BIP 341 — Taproot] [Bitcoin Optech — Schnorr signatures]

BIP340 uses x-only public keys and tagged hashes to bind protocol contexts. [Bitcoin Optech — Schnorr signatures] [Bitcoin Core — secp256k1 verification]

Linearity enables multisignature constructions such as MuSig2 but does not make naive signature addition safe. [BIP 340 — Schnorr Signatures] [Bitcoin Core — Script interpreter]

Legacy and SegWit v0 inputs still use ECDSA; activation did not replace every historical signature rule. [Bitcoin Core — secp256k1 verification] [Bitcoin Core — Script interpreter]

BIP340 uses x-only public keys and tagged hashes to bind protocol contexts. [Bitcoin Optech — Schnorr signatures] [BIP 340 rendered specification]

Linearity enables multisignature constructions such as MuSig2 but does not make naive signature addition safe. [BIP 341 — Taproot] [Bitcoin Core — secp256k1 verification]

Legacy and SegWit v0 inputs still use ECDSA; activation did not replace every historical signature rule. [BIP 340 — Schnorr Signatures] [BIP 340 rendered specification]

BIP340 uses x-only public keys and tagged hashes to bind protocol contexts. [Bitcoin Core — Script interpreter] [BIP 340 rendered specification]

For the clearest picture, read this entry together with Taproot, MuSig2, Multisig, Bitcoin Script. The reverse links also lead from SHA-256, MuSig2, Nostr, FROST.

DOC · 001BIP 340 — Schnorr SignaturesSpecificationDOC · 002BIP 341 — TaprootSpecificationDOC · 003Bitcoin Optech — Schnorr signaturesDocumentationDOC · 004Bitcoin Core — secp256k1 verificationDocumentationDOC · 005Bitcoin Core — Script interpreterDocumentationDOC · 006BIP 340 rendered specificationSpecification
Reviewed 1 August 2026Source-first · No investment advice