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Bitcoin : récupération et Lightning

Bitcoin timelocks: a calendar condition versus a coin’s age

Absolute and relative locks start their clocks in different places.

Mis à jour le 30 septembre 2026 · MASTR Labs

Les articles et schémas techniques sont en anglais. La navigation est disponible en 7 langues.

Guides de référence
  1. Two kinds of waiting
  2. A lock is a condition, not a scheduled payment
  3. Which clock is actually used?
  4. Recovery design needs an exit story
  5. Exemple concret
  6. Sources et originaux

Two kinds of waiting

An absolute timelock restricts spending before a specified block height or time condition. A relative timelock measures a delay from the confirmation of the output being spent. BIP-65 introduces CHECKLOCKTIMEVERIFY; BIP-68 and BIP-112 define the relative sequence-lock mechanism and CHECKSEQUENCEVERIFY. They do not use a human calendar in the same way as an appointment app. 1 2 3

A lock is a condition, not a scheduled payment

Reaching the required height or age can make a spending path eligible. It does not create a signature, pay a fee or broadcast a transaction. Other script conditions still apply. A recovery path can therefore combine a delay with a particular key; an owner must retain that key and a compatible way to construct the eventual spend.

Which clock is actually used?

Block-height locks depend on blocks, not guaranteed minutes. Time-based consensus checks use the specified median-time rules rather than a wallet’s local wall clock. Relative time locks use a defined granularity. Converting these mechanisms into ‘exactly 24 hours’ without explaining the assumptions gives users false precision. Wallet interfaces should expose the condition and whether it has become satisfied.

Recovery design needs an exit story

A delayed alternative can give an owner time to respond to an unwanted action, but only if someone monitors the relevant state and has a usable response path. A long delay can also lock a legitimate owner out during an emergency. Document who can use each branch, the starting event for the delay and what happens if the monitoring service disappears.

Where does the clock start?
Schéma explicatif. Ouvrir en pleine taille. Credits ↗ A satisfied timelock permits a path. It does not send a payment.

Exemple concret

An absolute path opens after block height H, regardless of when the output was funded. A relative path requiring 144 blocks starts from that output’s confirmation. Funding a new output tomorrow starts a new relative wait; it does not move the absolute height H.

Sources et originaux

  1. BIP-65: CHECKLOCKTIMEVERIFY
  2. BIP-68: relative lock-time
  3. BIP-112: CHECKSEQUENCEVERIFY

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