Geez ,
Not Jeez, but FSM. It's only FSM who can freely issue IOUs on LN. And not only that, FSM can also instantly derive private keys from public ones, calculate preimages of any hashes and so on. So better start to worship FSM, before it's too late.
Now seriously. Not only you don't understand how LN is supposed to work. It's OK to not understand it. Even among cryptocurrency enthusiasts most people don't understand it.
But do you believe that so many people (including cryptocurrency experts) are so stupid, that they can't distinguish IOUs from BTC?
Why do you think system so complex, that you can't even understand it, needed, if the purpose is just to exchange IOUs?
I recommend you reading this
article. BTW I always enjoy reading Aaron van Wirdum's articles, he's a great author.
And here is my description of bidirectional micropayment channel. LN works over these channels.
For those who prefer not to puzzle over what is written below, here's a short summary. LN transactions transfer knowledge necessary to redistribute funds locked in multisinature outputs. It's important:
bitcoins are first locked and only after that they can be transacted over LN. It even would be wrong to say that LN bitcoins are "backed" 1to1 by real bitcoins, because LN bitcoins are the same bitcoins that everybody transacts today onchain.
Bidirectional payment channel.
Opening the channel.
1) Alice and Bob create transaction tx1 which sends 5 BTC from Alice and 5 BTC from Bob to a multisignature 2of2 output o1, neither party signs this transaction yet.
2) Alice and Bob create secrets Sa and Sb, and exchange hashes of those secrets (Ha and Hb): Ha goes to Bob, Hb goes to Alice. Alice and Bob will need those hashes to create transactions tx2 and tx3 at steps 3 and 4.
3) Alice creates transaction tx2 which spends o1 and creates 2 new outputs: 5 BTC go Alice (o2), 5 BTC go to output o3, which can be spent in 2 different ways: a) Bob can spend it himself, but only after significant timeout of say 1000 blocks; b) Alice can spend it herself, but only if she provides preimage of Hb i.e. Sb. Alice signs tx2 and sends it to Bob.
4) Bob creates transaction tx3 which spends o1 and creates 2 new outputs: 5 BTC go to Bob (o4), 5 BTC go to output o5, which can be spent in 2 different ways: a) Alice can spend it herself, but only after significant timeout of say 1000 blocks; b) Bob can spend it himself, but only if he provides preimage of Ha i.e. Sa. Bob signs tx3 and sends it to Alice.
5) tx1 is signed, broadcast and confirmed.
The channel now is considered open. 5 BTC from Alice and 5 BTC from Bob are now locked in output o1. Both parties however are safe. If Alice disappears, Bob only needs to sign and broadcast tx2 (Alice already signed it), then wait some time, and get his refund from o3. If Bob disappears, Alice can do the same thanks to tx3. Under normal circumstances tx2 and tx3 aren’t broadcast.
Updating the channel (conducting payments).
1) Alice wants to pay 1 BTC to Bob. Both parties create new secrets S2a, S2b, and exchange hashes of those secrets: H2a and H2b.
2) Alice creates transaction tx4 which spends o1 new way: 4 BTC go to Alice (o6), 6 BTC go to output o7, which can be spent in 2 different ways: a) Bob can spend it himself, but only after significant timeout of say 1000 blocks; b) Alice can spend it herself, but only if she provides preimage of H2b i.e. S2b. Alice signs tx4 and sends it to Bob.
3) Bob creates transaction tx5 which spends o1 similar way to tx4: 6 BTC go to Bob (o8), 4 BTC to output o9, which can be spent in 2 different ways: a) Alice can spend it herself, but only after significant timeout of say 1000 blocks; b) Bob can spend it himself, but only if he provides preimage of H2a i.e. S2a. Bob signs tx5 and sends it to Alice.
4) Alice sends Sa to Bob.
5) Bob sends Sb to Alice.
Now the channel is updated. If either party disappears, remaining party will receive his/her refund thanks to tx4 or tx5. But what prevents Alice from broadcasting tx3 which indirectly pays her 5 BTC, instead of her current share of 4 BTC? Tx3 doesn’t immediately pay 5 BTC to Alice, it immediately pays 5 BTC to Bob and creates o5 which Alice can redeem only after waiting 1000 blocks. But Bob now has Sa, and if he sees tx3 on the chain, he can immediately spend o5, because now he possesses Sa, thus taking all 10 BTC from the channel. Please note, that despite tx3 was created by Bob, his version of this transaction lacks Alice’s signature. Normally only tx1 is broadcast yet. This way the channel can be updated many times. After each update, only the last pair of transactions can be safely broadcast to close the channel and receive proper share of channel funds, because all previous secrets are known to respective counterparties.
Closing the channel.
Both parties know, that they can’t cheat each other. So when they decide to close the channel, one of them (let it be Alice) creates a transaction that spends o1 according to the latest state of the channel, signs it, and sends to Bob. He checks that funds are split fairly, signs it and broadcasts it. This transaction is the second and the last to hit the chain, for the whole lifetime of the channel.
LN adds a third output to intermediate transactions like tx3, tx4, but gist remains the same: transactions transfer knowledge necessary to redistribute funds locked in multisignature outputs created when channels are opened.
It's a good exercise to think what would happen if either party starts to misbehave at any step. If you find any flaw in my description of the protocol, let's discuss it.