{"id":38011,"date":"2024-06-18T13:01:00","date_gmt":"2024-06-18T10:01:00","guid":{"rendered":"https:\/\/forklog.com\/en\/?p=38011"},"modified":"2025-08-30T00:31:21","modified_gmt":"2025-08-29T21:31:21","slug":"what-are-schnorr-signatures-and-how-are-they-used-in-bitcoin","status":"publish","type":"post","link":"https:\/\/forklog.com\/en\/what-are-schnorr-signatures-and-how-are-they-used-in-bitcoin\/","title":{"rendered":"What are Schnorr signatures and how are they used in Bitcoin?"},"content":{"rendered":"
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What are Schnorr signatures?<\/h2>\n

Schnorr signatures are a digital-signature scheme proposed<\/a> in 1991 by the German cryptographer Claus Peter Schnorr. <\/p>\n

In 2020 it was included in BIP-340<\/a> as an alternative to the Elliptic Curves Digital Signature Algorithm (ECDSA<\/a>). The proposal was implemented on the Bitcoin network in November 2021.<\/p>\n<\/div>\n

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What is a digital signature?<\/h2>\n

A digital signature is a mathematical scheme to verify two key characteristics of a digital message: authenticity (sent by a specific user) and integrity (not altered in transit).<\/p>\n

Using digital signatures, the Bitcoin protocol confirms the binding of a private key to a specific public address. Satoshi Nakamoto stressed their importance in the white paper<\/a> of the first cryptocurrency:<\/p>\n

\n“We define an electronic coin as a chain of digital signatures. Each owner transfers the coin to the next by digitally signing a hash of the previous transaction and the public key of the next owner and adding these to the end of the coin. A payee can verify the signatures to verify the chain of ownership.”<\/em><\/cite><\/p><\/blockquote>\n<\/div>\n

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Which digital signatures does Bitcoin use?<\/h2>\n

Originally the first cryptocurrency used only ECDSA \u2014 an open-source algorithm widely applied in 2008. Satoshi Nakamoto\u2019s choice is linked to the fact that, by the time the Bitcoin white paper was published, Schnorr signatures had not been standardised.<\/p>\n

In 2014 a discussion began<\/a> on Bitcointalk about introducing Schnorr signatures into Bitcoin\u2019s protocol, and six years later Pieter Wuille, Jonas Nick and Tim Ruffing standardised them in BIP-340<\/a>. <\/p>\n

Schnorr signatures were implemented on 14 November 2021 as part of the Taproot upgrade at block height #709,632. Since then they have been used alongside ECDSA.<\/p>\n<\/div>\n

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How do Schnorr signatures improve on ECDSA?<\/h2>\n

The authors of BIP-340 highlight three main advantages of Schnorr signatures:<\/p>\n