Thread by @willcl_ark

1/ With Lntenna-python you can send a @blockstream Satellite message from an off-grid node, using a Submarine Swap over @goTenna mesh network:

2/ To send a message to most of the global landmass from an off-grid device - with no direct internet connection - we leverage the Blockstream Satellite Transmission Service
blockstream.com/satellite-queu…

3/ Because payment for the Blocksat service is via #lightning and our off-grid device only has a full #bitcoin node, we need somebody else to *trustlessly* pay on our behalf...

4/ A Submarine Swap enables us to pay a lightning invoice directly with bitcoin, and to verify locally ourselves that in order to claim the bitcoin we sent, the Submarine Swap provider MUST pay the lightning invoice first, sending our message to the world.

5/ @alexbosworth's Submarine Swap Service allows us to do just that via a convenient API
submarineswaps.org

6/ First the Lntenna-python Client will request a quote from the Gateway server. The Gateway will query Blockstream and submarineswaps.org on its behalf, and return the lightning invoice and submarine swap quote via the mesh

7/ The client can decode the lightning invoice and verify the signatures match the hardcoded pubkeys from Blockstream. It can also decode the submarine swap redeem script to ensure that the submarine swap provider MUST fulfil the invoice to claim (spend) the bitcoins we send them

8/ When the client accepts the quotations, Lntenna-python will generate a bitcoin transaction to satisfy the swap quote. The raw bitcoin transaction is sent to the Gateway via the mesh, and uploaded to the bitcoin P2P network.

9/ When the swap is executed, the swap provider will return to us the preimage of the lightning invoice, which we can validate against the lightning invoice on the mesh client, to verify the invoice was paid.

10/ You can read more about the full process and find links to the code repo in this blog post:
inthemesh.com/archive/lntenn…