Timelock
Also · nLockTime · CLTV · CSV
A timelock is a Bitcoin script condition that keeps a transaction or an output from being spent before a given block height or time. Layer 2s are built on it.
A timelock makes a spend invalid until a point in the future, expressed either as a block height or as a timestamp. It can be absolute, “not before block 900,000”, or relative, “not until 144 blocks after this output was confirmed”. Bitcoin offers both, through the nLockTime field and the CheckLockTimeVerify and CheckSequenceVerify opcodes.
Timelocks are the quiet workhorse of every layer 2. A Lightning channel gives the cheated party a window to react. An Ark or Spark user can exit unilaterally once a delay has passed. A vault can impose a cooling-off period on withdrawals. Without a way to say “not yet”, none of these contracts would hold.
In French · Timelock
