Hashed Time-Locked Contract (HTLC)
A contract that locks funds with both a hash condition and a deadline, enabling atomic swaps and routed payments.
- Also known as
- htlc
An HTLC locks funds behind two conditions: a recipient can claim by revealing the preimage to a known hash before a deadline, or the sender can refund after the deadline. This creates an all-or-refund structure for payments that cross parties or chains.
The contract contains a hash H, a claim path requiring a value x where hash(x)=H, and a refund path that becomes valid after time T. Timelocks may be absolute, such as CLTV, or relative, such as CSV.
HTLC safety depends on secure hash functions, correct scripts, and timelocks that leave enough time to react. Cross-chain designs must account for different block times, reorg risk, fees, and mempool congestion.
Related terms
3 linkedExplore connected entries beyond the alphabetical index.
Atomic Swap
→A trustless exchange of assets across chains using time-locked contracts.
Escrow
→Escrow holds funds until agreed conditions are met, using a trusted custodian, multisig, or smart contract logic.
Hash
→A fixed-size digest produced by a one-way function, used for data integrity, identifiers, signatures, and proof-of-work.
All terms and definitions may update as the Cryptionary improves.
