Observe these 3 characteristics:
- UTXOs
- Fund destinations
- Time conditions (timeouts)
Bob's signature cannot be reused for another transaction that changes any of these parameters. If Alice tries to create a second transaction using the same UTXOs, Bob's signature will not be valid for this new transaction
As I mentioned above, PTLCs often combine adaptor signatures with multi-party signatures, so:
- Alice deposits her funds into a multi-sig address that requires collaboration between Alice and Bob to spend the funds
- Bob holds a signature that is only valid for the specific transaction claiming the funds according to the swap terms (by presenting the secret s)
Refund Mechanism
As also mentioned earlier, in addition to swap transactions, there is a refund path that Bob can use in case Alice disappears or does not complete the swap:
- Bob does not need Alice's tweak t to execute the refund
- After the timeout tB, he can sign the refund transaction using his own key, independently of Alice
Consider the following scenario:
Bob signs a specific transaction that can only be executed with Alice's secret s, and Alice cannot sign additional transactions spending the same UTXOs without Bob's collaboration
Thus, Alice cannot simply spend the UTXOs in another way without invalidating Bob's signature. If she attempts a double spend, the original transaction with Bob's signature will still be valid, and he will be able to execute the refund after the timeout
After this magnificent explanation, do I deserve a donation?
- UTXOs
- Fund destinations
- Time conditions (timeouts)
Bob's signature cannot be reused for another transaction that changes any of these parameters. If Alice tries to create a second transaction using the same UTXOs, Bob's signature will not be valid for this new transaction
As I mentioned above, PTLCs often combine adaptor signatures with multi-party signatures, so:
- Alice deposits her funds into a multi-sig address that requires collaboration between Alice and Bob to spend the funds
- Bob holds a signature that is only valid for the specific transaction claiming the funds according to the swap terms (by presenting the secret s)
Refund Mechanism
As also mentioned earlier, in addition to swap transactions, there is a refund path that Bob can use in case Alice disappears or does not complete the swap:
- Bob does not need Alice's tweak t to execute the refund
- After the timeout tB, he can sign the refund transaction using his own key, independently of Alice
Consider the following scenario:
Bob signs a specific transaction that can only be executed with Alice's secret s, and Alice cannot sign additional transactions spending the same UTXOs without Bob's collaboration
Thus, Alice cannot simply spend the UTXOs in another way without invalidating Bob's signature. If she attempts a double spend, the original transaction with Bob's signature will still be valid, and he will be able to execute the refund after the timeout
After this magnificent explanation, do I deserve a donation?