nLockTime

This page is a stub. Help by expanding it.

nLockTime is a parameter of a transaction, that, if any input indicates so (by having nSequence not equal to UINT_MAX), mandates a minimal time (specified in either unix time or block height), before which the transaction cannot be accepted into a block. If all inputs in a transaction have nSequence equal to UINT_MAX, then nLockTime is ignored.

Since BIP68, a new meaning has been given to the nLockTime and nSequence fields. Given a transaction,

• If the most significant bit (1<<31) is set
  • If the 23rd bit (1<<22) is set
    • Specifies a time in units of 512 seconds. The transaction can only be included in a block if block_time > nLockTime * 512.
  • Otherwise
    • Specifies a block height before which the transaction can not be included in a block.
• Otherwise
  • the transaction can be included in any block

See Also

• lock_time in the protocol specification
• Timelock
• BIP68
• The CHECKLOCKTIMEVERIFY opcode in BIP65
• The CHECKSEQUENCEVERIFY opcode in BIP112