Expiry is enforced by verification logic, not by the bytes aging automatically.
LET’S PICTURE IT
A permission slip expires only when the accepting desk checks its date.
SEE IT FOR YOURSELF
From a public address to a verified signatureStep 1 / 4
An address is public receiving information. It is not the private key that authorizes actions.
An address is public receiving information. It is not the private key that authorizes actions.The local signing system uses secret authorization material. It produces a signature; the private key is not sent along with it.A verifier checks the signed request under the account’s rules. A valid signature does not by itself prove that the action is safe.Balances belong to network state. A wallet is an interface and signing system, not a box containing coins.
Animated local teaching model. No wallet, RPC or live blockchain data. Some labels and hashes are abbreviated for readability.
Bind the deadline to the authorization
Include the expiry field in the signed content. A deadline displayed only by the website cannot constrain a verifier that does not check it.
Check the chosen comparison
The protocol decides whether equality at the deadline is accepted. Record whether validity means now is less than or less than or equal to the deadline.
Keep replay control separate
A deadline limits a time window but can still allow repeated redemption inside that window. Use nonce or consumption rules where the action should be single-use.
Use the relevant time source
On-chain checks normally use the chain’s timestamp context, not the user’s browser clock. Explain units and boundary assumptions in tests.
Inspect the distinction
signed deadline: 1,000 (toy timestamp)
rule: current timestamp <= deadline
1,000 accepted; 1,001 rejected
Nonce control is still a separate requirement.
These are local teaching values, not a signature request or a live-chain lookup.