Elliptic Curve Signatures

Let's dig into when, where, and how Bitcoin uses Elliptic curve signatures in transactions. This chapter covers the importance of signatures to transactions, the three purposes these signatures serve, and how they are applied.

Digital Signatures (ECDSA)

Verifying the Signature

To verify the signature, one must have the signature (R and S), the serialized transaction, and the public key (that corresponds to the private key used to create the signature). Essentially, verification of a signature means "Only the owner of the private key that generated this public key could have produced this signature on this transaction".

The signature verification algorithm takes the message (a hash of the transaction or parts of it), the signer's public key and the signature (R and S values), and returns TRUE if the signature is valid for this message and public key.