Digital Signature

Definition

A digital signature is a cryptographic value that allows others to verify that a message was authorized using a particular private key. Verification uses the corresponding public key and detects changes to the signed information. In cryptocurrency systems, signatures help satisfy spending conditions without revealing the private key itself. Bitcoin uses signature schemes including ECDSA and Schnorr, depending on the output and spending arrangement. A signature is not encryption: it normally does not conceal the transaction's contents. Nor does it automatically establish the signer's real-world identity, because the relationship between a person and a key may be unknown. Wallet prompts deserve careful review because a valid signature can authorize an unwanted transaction just as effectively as an intended one. Security depends on the signing algorithm, correct implementation, protected keys, and a clear understanding of the message or transaction being approved.