3 upvotes, 3 direct replies (showing 3)
View submission: ⚡ Lightning Network Megathread ⚡
A and B have a channel. 1 BTC each. A sends B 0.5 BTC. B sends back 0.25 BTC. Balance should be A = 0.75, B = 1.25. If A gets disconnected, B can publish the first Tx where the balance was A = 0.5 and B = 1.5. If the node B does in fact attempt to cheat by publishing an old state (such as the A=0.5 and B=1.5 state), this cheat can then be detected on-chain and used to steal the cheaters funds, i.e., A can see the closing transaction, notice it's an old one and **grab all funds in the channel (A=2, B=0)**.
Does that mean that both A and B have the permission to move ALL the funds in the channel (both A's and B's Bitcoin)? Does that mean that both A and B can just grab all the balance at any given time? Could A or B take all the BTC before the timer (CLTV) expire and essentially steal all the BTC in the channel?
Comment by Godspiral at 12/01/2018 at 19:07 UTC
3 upvotes, 2 direct replies
I have the same question, but add is there no way to make it appear as though B is the one cheating in order to pull off this move as a "scam".
I'm in fact not sure if what you quoted is accurate. If instead the best that A can do is post the "true" .75/1.25 version.
Comment by fryguy_22 at 12/01/2018 at 20:58 UTC
2 upvotes, 1 direct replies
Good question. No. In the example you quote, A can ONLY grab all the funds in the channel if B has submitted a "cheat" (old) state. To grab these funds, A would have to provide proof of a more updated state (signed by both parties). They do not have the ability to move the funds at will. They do have the ability to use the most recent double-signed state to close the channel, but that does not harm either party (beyond just closing out the channel at the most recently agreed balance)
Comment by jaydoors at 21/01/2018 at 23:57 UTC
1 upvotes, 0 direct replies
AFAIK A now has a secret which they can use to take all the funds after the old state tx is broadcast. This exchange of secrets when agreeing the new state is what means old states are not useable: both A and B now have a secret from each other which lets them take ALL the channel funds if an old state is broadcast.
That sound right?