Bitcoin Thunderbolt Protocol Visualization
An interactive walkthrough of the key off-chain transfer process.
Phase 1: Prepare
Alice wants to make her Bitcoin UTXO available for off-chain transfers via Thunderbolt.
Action: Alice locks her UTXO on the Bitcoin Network.
This UTXO is now controlled by a joint key: Alice + Committee.
On-Chain: A transaction confirms this lock.
Off-Chain Ledger (Committee): Records Alice as the initial owner of the UTXO.
Result: The UTXO is ready for off-chain transfers. Alice is the current owner.
Phase 2: Transfer (Alice → Bob)
Alice transfers the UTXO ownership to Bob off-chain.
Actions:
- Alice creates her tweaked signature part S'_Alice_Bob using a secret shared with Bob.
- Committee creates its tweaked signature part S'_Committee_Bob using a secret shared with Bob.
- Committee verifies the tweaks and updates its off-chain ledger.
Off-Chain Ledger (Committee): Bob is now the owner of the
UTXO. Alice can no longer spend it.
Result: Bob is the new off-chain owner. The transfer was instant and didn't touch the Bitcoin blockchain.
Phase 3: Reassign (Bob → Carol)
Bob transfers the UTXO ownership to Carol off-chain.
Actions: (Similar to Alice
→ Bob transfer)
- Bob creates his tweaked signature part S''_Bob_Carol using a secret shared with Carol (this modifies his previous share).
- Committee creates its new tweaked signature part S''_Committee_Carol using a secret shared with Carol.
- Committee verifies and updates its off-chain ledger.
Off-Chain Ledger (Committee): Carol is now the owner of the
UTXO. Bob can no longer spend it.
Result: Carol is the new off-chain owner. Another instant, off-chain transfer.
Phase 4: Finalize (Carol Redeems On-Chain)
Carol decides to redeem the UTXO on the Bitcoin Network.
Actions:
- Carol requests the Committee's final tweaked signature share (S''_Committee_Carol).
- Carol combines her final share (S''_Bob_Carol) with the committee's share.
- Carol mathematically reverses all accumulated tweaks to reconstruct the original valid Schnorr signature for the UTXO.
- Atomic Swap with Committee:
- Committee facilitates spending the original UTXO (funds to Committee temporarily). (Tx1)
- Committee escrows funds to a joint Carol + Committee address. (Tx2)
- Carol + Committee move funds from escrow to Carol's sole address. (Tx3)
On-Chain: The
UTXO is spent, and Carol receives the Bitcoin.
Off-Chain Ledger (Committee): Marks the
UTXO as spent.
Result: Carol has successfully redeemed the Bitcoin. The Thunderbolt off-chain lifecycle for this UTXO is complete.
Process Complete!
The Thunderbolt UTXO has been prepared, transferred off-chain multiple times, and finally redeemed on the Bitcoin network.
Click "Reset" to start over.