Signing
Pronunciation: SY-ning
Also known as: Digital Signing, Cryptographic Signing
Definition
Signing is the use of a cryptographic secret or signing authority to produce a digital signature that authenticates data and permits others to verify authorization or integrity.
Overview
How it works and why it matters
Signing is using a secret cryptographic credential to approve a specific message. A wallet may sign a login challenge, a structured authorization or a transaction; the real-world effect is not always the same. A sound interface explains the domain, chain, contract, recipient, value, expiry and nonce where relevant.
Important technical and operational details
It is a general cryptographic action that can apply to transactions, messages, software, documents, or protocol data.
Operationally, secure workflows identify the exact payload and domain, protect the key, authenticate the requester, apply policy, and retain verifiable audit evidence.
The principal risk is that signing ambiguous or attacker-controlled data can authorize unintended actions even when the private key remains technically secure. High-value actions should be independently reviewed before execution.
Practical decision points
Most users encounter several classes of signatures: transaction signing spends or authorizes value, message signing proves key control, and structured signing approves data with typed fields. A signature is mathematically bound to its payload, but that payload may be unsafe, misleading or reused if the protocol lacks nonces and domain separation. Before signing, verify the expected origin, action, chain and expiration; when authorizing token permissions, also inspect the spender and allowance. Security reviews should treat wallet UI, browser extensions, contract code and signer policy as one complete attack surface. The private key should never be revealed to the application requesting a signature.
Related concepts
Offline Signing; Air-Gapped Signing; Secure Signing
Further reading
Example
An employee is asked to sign an apparently harmless message to log in. The message actually authorizes a token permit for a spender. The signature alone can later enable a transfer without a second on-chain approval transaction, so the employee must inspect the signed contents.
Comparison
A valid signature proves control of the relevant key, not that the signer understood the request. Signing should not be treated as synonymous with broadcasting, execution or final settlement.
Key Takeaway
A signature approves precisely the message or authority represented by its payload.
Sources
- EIP-712: Typed Structured Data Hashing and Signing — Ethereum Improvement Proposals (2026-08-02)
- BIP 174: Partially Signed Bitcoin Transaction Format — Bitcoin Improvement Proposals (2026-08-02)
- Clear Signing Overview — Ledger Developer Portal (2026-08-02)