ECDSA
The Elliptic Curve Digital Signature Algorithm, the cryptographic signing scheme that Bitcoin and (for externally owned accounts) Ethereum use to authorize transactions.
ECDSA, the Elliptic Curve Digital Signature Algorithm, is a specific digital signature (see Kaavon's "Digital Signature" glossary definition) scheme built on elliptic curve cryptography (see Kaavon's "Elliptic Curve Cryptography" glossary definition), and is the signature algorithm Bitcoin uses for all transactions, and that Ethereum uses for transactions signed by an ordinary externally owned account's private key. A valid ECDSA signature proves that whoever produced it holds the private key corresponding to a given public key, without ever revealing the private key itself.
ECDSA has been a foundational building block of crypto since Bitcoin's creation, though it has some practical limitations compared to newer alternatives like Schnorr signatures (see Kaavon's "Schnorr Signature" glossary definition) — Schnorr signatures support cleaner signature aggregation across multiple signers, which is part of why Bitcoin's Taproot (see Kaavon's "Taproot" glossary definition) upgrade introduced Schnorr as an addition alongside, rather than a replacement for, ECDSA.
Examples
- Every Bitcoin transaction is authorized by an ECDSA signature, proving the spender controls the private key corresponding to the funds being spent.
- Schnorr signatures, introduced alongside ECDSA through Bitcoin's Taproot upgrade, support more efficient signature aggregation across multiple signers than ECDSA does.