Digital Signature

Overview

A digital signature is generated by applying a signature algorithm to a private key and a precisely encoded message or message digest. Signature Verification uses the corresponding public key and the same signed data. If any signed field changes, the signature should fail. This gives blockchain nodes a way to reject unauthorized transfers or messages without learning the private key that produced the signature.

The signed content is as important as the cryptographic algorithm. A wallet may display an amount and destination, while the actual bytes also contain a network identifier, nonce, fee, contract call, validity period, or typed-data domain. Secure applications must make sure the user approves the same representation that is later submitted. Otherwise a technically valid signature can authorize a request whose meaning was hidden, ambiguous, or incorrectly decoded.

Different networks use schemes such as ECDSA, EdDSA, Schnorr, or BLS, each with its own encoding and verification rules. Some protocols support multiple signers, threshold signing, or an Aggregate Signature to reduce bandwidth. Keys and signatures are not interchangeable across algorithms. Implementations must also reject malformed values, enforce domain separation, and follow protocol rules for canonical encoding and replay protection.

For payment operations, a valid signature establishes authorization at one step, not settlement. The transaction can still be rejected for insufficient balance, invalid state, expired references, or a failed contract call. Teams should preserve the signed payload, signer identity, algorithm, network, and verification result, then separately track execution and finality. Compromised keys can produce perfectly valid signatures, so key security and approval policy remain essential.