@supertestnet diving deep explaining his recent papa swaps #1156810 with these comparison diagrams, I can now see the key differences between Traditional Submarine Swaps and Papa Swaps:
The name Papa Swap comes from Papa Class, a group of Cold War submarines that included the world’s fastest declassified submarine – the Soviet K-222. As those are the fastest submarines, these are the fastest submarine swaps. @supertestnet - X
Key Innovation: The Papa Swap Address
The Papa Swap creates a special address that's derived from:
Server + User + Secret| Diagram | ||
|---|---|---|
| Name | Papa Swap | Submarine Swap |
| Process Flow | ||
1. | User requests the same swap (1 LN btc for 1 L1 btc) | User initiates a swap request to exchange 1 LN btc for 1 L1 btc |
2. | Server creates a 32-byte secret and generates the Papa swap address | Server creates a Bitcoin address with an HTLC (Hash Time Locked Contract) |
3. | Server provides a signature allowing the user to spend from this address only if they learn the secret | Server generates a HODL invoice locked to a secret hash and sends it to the user |
4. | User gives the server a signature for a traditional HTLC | User pays the Lightning invoice (1 LN btc) |
5. | Server sends a Lightning invoice locked to the secret | Server deposits 1 L1 btc into the HTLC on-chain |
6. | User pays the Lightning invoice (1 LN btc), revealing the secret | Server retrieves the secret from the Lightning payment and settles the HTLC |
7. | Server gets paid and the swap completes | User can withdraw the on-chain bitcoin after revealing the secret (with a 2-week timelock safety) |
Main Differences
1. Address Generation:
- Submarine: Uses standard HTLC with hash locks
- Papa: Uses a unique address derived from Server + User + Secret combination
2. Security Model:
- Submarine: Relies on timelock mechanisms and hash revelation
- Papa: Uses cryptographic signatures that are only valid when the secret is known
3. Efficiency:
- Submarine: Requires multiple on-chain transactions and timelock waiting periods
- Papa: More streamlined process with fewer on-chain operations
4. Trust Requirements:
- Submarine: Built-in timelock safety (2-week withdrawal window)
- Papa: Relies more heavily on the cryptographic properties of the Papa swap address
Look's like the Papa Swap optimize the process and reduces the complexity, and potentially the costs —compared with submarine swaps— by using a more sophisticated address construction method.
A good explanation is here at min 1:47:00
previously shared here #1058203