TYPE 0x0104 · TIMELOCK FAMILY

CLTV_TIME

Absolute timelock in Unix time (BIP 65). Transaction cannot be included until Unix timestamp reaches the specified value. Values ≥ 500,000,000 are interpreted as timestamps.

Timelock Invertible

Ladder Diagram

Fields

Field	Data Type	Size	Side	Description
timestamp	NUMERIC	1-4 B	Conditions	Unix timestamp (values ≥ 500000000 interpreted as time)

No witness fields required — evaluation uses the median-time-past from the evaluation context.

Wire Format Breakdown

0x0104 0 1 NUMERIC · 3B Conditions = 4 + 5 = 9 bytes

0x0104 0 0 Witness = 4 bytes (empty block)

Total 15 bytes

Evaluation Logic

1.Read timestamp from NUMERIC field. Negative → ERROR

2.CheckLockTime(value) — value interpreted as Unix timestamp. If fails → UNSATISFIED

3.Pass → SATISFIED

Return Values

Condition	Result
Missing NUMERIC field	ERROR
Negative timestamp value	ERROR
median_time_past ≥ timestamp	SATISFIED
median_time_past < timestamp	UNSATISFIED

JSON Wire Format

Conditions (locked until 2027-01-01 00:00:00 UTC = 1798761600)

{
  "type": "CLTV_TIME",
  "inverted": false,
  "fields": [
    { "type": "NUMERIC", "value": 1798761600 }
  ]
}

This locks the UTXO until January 1, 2027 (Unix timestamp 1798761600). The transaction will be rejected by consensus until the median-time-past reaches that point.

Worked Example

timestamp = 1798761600 (2027-01-01 00:00:00 UTC)

MTP 1798761599 (2026-12-31 23:59:59): 1798761599 < 1798761600 → UNSATISFIED

MTP 1798761600 (2027-01-01 00:00:00): 1798761600 ≥ 1798761600 → SATISFIED

MTP 1801440000 (2027-02-01 00:00:00): 1801440000 ≥ 1798761600 → SATISFIED

Use Cases

Calendar-Specific Unlocks

Funds that unlock on a specific calendar date — useful for grant agreements, employment contracts, or any arrangement tied to real-world dates rather than block heights.

Expiry Dates for Options/Futures

Financial contracts with hard expiry timestamps. The option or futures contract output can only be exercised after the specified Unix timestamp, enforced by consensus.

Event-Gated Spending

Outputs locked until a known future event time (e.g., end of an auction, settlement deadline). The timestamp provides a deterministic cutoff anchored to wall-clock time rather than block height.

← CLTV TAGGED_HASH →