Locktime
A transaction field or script condition that delays when funds can be spent or when a transaction becomes valid.
Locktime is a Bitcoin-style transaction feature that prevents a transaction from being valid until a specified block height or timestamp. It allows users and protocols to create delayed settlement or refund paths.
The nLockTime field is a 32-bit value. Values below 500,000,000 are interpreted as block heights; values at or above that threshold are interpreted as Unix timestamps. Input sequence numbers determine whether nLockTime is active.
Timelocks are important for payment channels, atomic swaps, escrow, and recovery transactions. They give honest participants a window to claim, refund, or dispute funds without trusting a counterparty.
Related mechanisms include CLTV for absolute timelocks inside scripts and CSV for relative timelocks based on how long an output has existed. These tools are more flexible than a transaction-level nLockTime alone.
Related terms
3 linkedExplore connected entries beyond the alphabetical index.
Hashed Time-Locked Contract (HTLC)
→A contract that locks funds with both a hash condition and a deadline, enabling atomic swaps and routed payments.
Escrow
→Escrow holds funds until agreed conditions are met, using a trusted custodian, multisig, or smart contract logic.
Confirmations
→The count of blocks confirming a transaction, usually including the block that first contains it.
All terms and definitions may update as the Cryptionary improves.
