Leave blank if you want the token to be redeemable by anyone after the lock expires.
WARNING: A refund lock never expires. Make sure the public key is correct!
NOTE: Not all Cashu wallets support refund public keys yet. Nostrly Cashu Redeem does.
NutLock History
About this tool
Cashu turns Bitcoin into ecash, enabling peer-to-peer transactions with near-perfect privacy. NutLock lets you lock a Cashu token to one or more public keys (Nostr NPUB or P2PK) for a set time. You can also specify the number of signatures required to unlock (multisig). After the lock expires, the token can be spent by anyone, or you can lock it permanently to one or more public keys, on an any one can sign basis.
This unlocks some cool use cases:
Clawback Tokens: (Alice locks to Bob, refund to herself)
Send ecash only the intended receiver can redeem. If they don’t claim it, you claw it back after the lock expires—no more wasted Nostr tips! Also supports offline sales that can’t be double-spent (when used with a DLEQ signature check), reclaimable if the deal falls through.
Inheritance Tokens: (Alice locks to herself, refund to Bob)
Nominate someone to “inherit” your token if you don’t spend it before the lock expires. You can even share it upfront if you want—the ultimate dead man’s switch!
Third-Party Refund Tokens: (Alice locks to Bob, refund to Carol)
Allows time-based “escrow” if Carol is a trusted third party. If the deal goes smoothly, Carol passes Bob the token to cash in. If it goes south, or Bob is late delivering, she can cash the token herself on lock expiry and arbitrate between Alice and Bob.
Open-Claim Tokens: (Alice locks to Bob, no refund lock)
Publicly post locked ecash that can only be redeemed by the intended receiver. If they don’t claim it, anyone can claim it after the lock time expires. Let the Nostr fun and games commence!
Multi-Signature Tokens: (Alice locks to Bob, Carol and herself – Any 2 can sign.)
Enables Ecash that is owned by multiple people, and atomic swaps / full escrow for important contracts.
⚠️ Don’t be reckless: Incorrect refund keys can permanently lock tokens!