Coin Freeze

A coin freeze is any Bitcoin script that prevents spending until a specific time or block height. The freeze is enforced by the protocol; no third party can release the funds early.

The two primitives:

• OP_CHECKLOCKTIMEVERIFY (CLTV): spend allowed only after an absolute reference - a block height or a UNIX timestamp. Useful for "spendable on June 1, 2030."
• OP_CHECKSEQUENCEVERIFY (CSV): spend allowed only after a relative interval - N blocks (or N units of time) since the parent transaction was confirmed. Useful for "spendable 1 year after this output was created."

Common applications:

• Self-imposed savings discipline. Lock coins for 1-5 years to prevent yourself from spending them impulsively during volatility.
• Inheritance setups. A spending path that becomes valid after 6 months without primary-key activity, designed to give heirs access if the primary holder dies or loses keys.
• Vaults. A clawback path that lets a cold key override a hot-key spend within a CSV window.
• Trustless escrow. Buyer and seller agree on a deal; coins are released after a delay or by mutual consent before the delay expires.
• Lightning channels. Every channel commitment uses CSV-locked outputs as part of the delayed justice mechanism.

What a coin freeze isn't:

• Reversible by anyone. Once locked in script, no one - including the original sender - can unfreeze the coins early. The freeze is enforced by every full node.
• Confidential. The lock script is on-chain. Anyone who can see the transaction can see when the funds become spendable.
• A perfect savings tool. A frozen UTXO is illiquid; the holder gives up the option to spend during the freeze window. That's the point, but it's a real cost.

Coin freezes are one of Bitcoin's underused primitives. Far more powerful than common wallet UX exposes, but increasingly accessible through tools like Sparrow's time-lock scripts, Liana's recovery-window wallets, and various vault implementations.