Can someone please answer me on this with LN ?

[LtMotioN]

Hi Forum
So if I open a channel and then shut down my PC for a few days, does the channel still remain open at all ?  I know I cant receive funds while my wallet is closed, but when I come back do I have to open a new channel and pay the associated fees again or can I still send money over LN with my old channel?

How does LN handle me going AWOL ?

[pebwindkraft]

So if I open a channel and then shut down my PC for a few days, does the channel still remain open at all ?

The way I understand is this: you can turn off your PC for a short time, the PC wouldn't close the channel. The channel opening and closing are the two transactions, which hit the blockchain (aka fees). These transactions are created as multisig funding tx, with a hash, a timelock and some logic to increase/decrease values. Now the hash is the relevant part, it is used as a revocation key. So if your counterparty finds out, you are not "on" anymore, they might activate this revocation key and as such close the channel.
If they don't, you can switch on your PC, and continue to send the signatures(aka payment updates) for the updated transaction to your counterparty.
And then there is a timelock in the channel: if your PC happens to be "off" when timelock is approaching, this might also close the channel.
However, there is an incentive in the lightning channel to stay online, or vice versa, a punishment. If you hold channels open, and turn off your PC, then the counterparty might be "hostage" to you (or your PC), and would have to wait for the timeout of the channel. Also, if one of the parties tries to cheat by posting an outdated commitment transaction, the counterparty can take all the bitcoins in the channel. This provides a strong incentive not to cheat.

Better leave your system "on" !

The best summary I could get for this so far is here on bitcoin.stackexchange: https://bitcoin.stackexchange.com/questions/55310/do-parties-in-a-lightning-network-channel-need-to-be-online

[Anti-Cen]

The money is safe in your wallet if you go AWOL but will get eaten away by interest charges on the BTC that the
banking hubs need to finance the other half of the Lightning ledger.

Crazy I know to have to pay interest on BTC that you own but this is the result of tokens being locked inside the
ledger so balances between you and the bank can change but the balance on the ledger always remains the same
as when the channel/ledger was created and this then gets settled on-block when the channel is closed.

Coins are not liquid in Lightning and are more like snooker balls that bump into each other inside the ledgers and
there is no plan "B" if the banking hub goes down for a few days apart from opening another bank account with
another hub and depositing coins in to the account which you might not want to do because regardless of the hub
banking costs you will still get hit with BTC miners fees and as you know, these can be high.

[LtMotioN]

So if I open a channel and then shut down my PC for a few days, does the channel still remain open at all ?

The way I understand is this: you can turn off your PC for a short time, the PC wouldn't close the channel. The channel opening and closing are the two transactions, which hit the blockchain (aka fees). These transactions are created as multisig funding tx, with a hash, a timelock and some logic to increase/decrease values. Now the hash is the relevant part, it is used as a revocation key. So if your counterparty finds out, you are not "on" anymore, they might activate this revocation key and as such close the channel.
If they don't, you can switch on your PC, and continue to send the signatures(aka payment updates) for the updated transaction to your counterparty.
And then there is a timelock in the channel: if your PC happens to be "off" when timelock is approaching, this might also close the channel.
However, there is an incentive in the lightning channel to stay online, or vice versa, a punishment. If you hold channels open, and turn off your PC, then the counterparty might be "hostage" to you (or your PC), and would have to wait for the timeout of the channel. Also, if one of the parties tries to cheat by posting an outdated commitment transaction, the counterparty can take all the bitcoins in the channel. This provides a strong incentive not to cheat.

Better leave your system "on" !

The best summary I could get for this so far is here on bitcoin.stackexchange: https://bitcoin.stackexchange.com/questions/55310/do-parties-in-a-lightning-network-channel-need-to-be-online

Cool so basically the channel stays open till the timelock ends or the other party closes it manually ? My channel stays open otherwise ?

[Kogs]

So if I open a channel and then shut down my PC for a few days, does the channel still remain open at all ?

The way I understand is this: you can turn off your PC for a short time, the PC wouldn't close the channel. The channel opening and closing are the two transactions, which hit the blockchain (aka fees). These transactions are created as multisig funding tx, with a hash, a timelock and some logic to increase/decrease values. Now the hash is the relevant part, it is used as a revocation key. So if your counterparty finds out, you are not "on" anymore, they might activate this revocation key and as such close the channel.
If they don't, you can switch on your PC, and continue to send the signatures(aka payment updates) for the updated transaction to your counterparty.
And then there is a timelock in the channel: if your PC happens to be "off" when timelock is approaching, this might also close the channel.
However, there is an incentive in the lightning channel to stay online, or vice versa, a punishment. If you hold channels open, and turn off your PC, then the counterparty might be "hostage" to you (or your PC), and would have to wait for the timeout of the channel. Also, if one of the parties tries to cheat by posting an outdated commitment transaction, the counterparty can take all the bitcoins in the channel. This provides a strong incentive not to cheat.

Better leave your system "on" !

The best summary I could get for this so far is here on bitcoin.stackexchange: https://bitcoin.stackexchange.com/questions/55310/do-parties-in-a-lightning-network-channel-need-to-be-online

Cool so basically the channel stays open till the timelock ends or the other party closes it manually ? My channel stays open otherwise ?

If the other party don't want to cheat on you and close the channel with the latest confirmed transaction, everything is fine.
The problems start if the other party close the channel with an old version of the transaction (where you get less coins than with the latest transaction) and you are offline. In this case you could lose coins..
If you are online and see this, you have the possibility to post a transaction where you can grab the coins of the other party.

Just an example:
Initial channel balance is 1 BTC from you and 1 BTC from the other party.
Then a transaction happens from the other party to you. Say you receive 0.2 BTC.
The current status of the channel (latest confirmed transaction) is 1.2 BTC for you, 0.8 BTC for the other side.

If the other party is closing the channel with the first transaction where he closes it with 1 BTC for him and you don't see it, he would be able to steal you those 0.2 BTC.
If you would be online and you recognize it, you could post a transaction (only then) to get the full 2 BTC from the channel.

This means, there is an incentive that all parties play fair and only post the last confirmed transaction and don't cheat. If someone cheats, and the other party see it, this party could then get the whole balance of the transaction and the cheater get nothing. That's the only reason why the lightning network works without trust on the other party.

But in case you are offline and don't have the possibility to see this kind of cheating on you, you would lose coins.

But I guess there will be possibilities (if not already possible with current implementations) to delegate this checks to someone who is online 24/7.

[DooMAD]

For anyone not fortunate enough to have Anti-Cen on ignore, it should be noted that their reply in this thread (along with being largely unhelpful to answering the question posed by the OP) is completely and totally factually inaccurate (as per usual).  If you leave your funds in an open channel but you don't need to transact, you categorically won't lose any funds unless the other party attempts to cheat.  If you wanted, your unused balance could even be used to route payments to other people and you could potentially earn some fees rather than paying them.  So it's basically the dead opposite of what Anti-Cen said.  As they've been repeating this same inaccurate portrayal of Lighting across multiple threads, despite it having been explained to them on more than one occasion, I honestly can't tell if it's deliberate misinformation on their part, or if they just have some sort of cognitive dysfunction and are incapable of comprehending it correctly.  Either way, please don't pay any attention to them.

There is a standard mining fee for both opening and closing channels.  There is also a (likely very small) fee each time you need to route through another channel to reach your intended recipient.  It's also worth noting that sometimes there will also be negative fees (i.e. you get money) if you're helping to rebalance someone else's channel.  There is no "interest" in the accepted sense of the word.

Back to the topic at hand, the replies from pebwindkraft and Kogs are accurate based on my understanding.  The channel does indeed stay open until the timelock ends or the other party closes it manually, but if you're offline for too long, there are some risks if you're dealing with people you don't know and trust not to steal from you.  You certainly don't have to be online 24/7 to make it work, though.  You just have to check it often enough to ensure it's all above board.

[Anti-Cen]

For anyone not fortunate enough to have Anti-Cen on ignore, it should be noted that their reply in this thread blur... blur ... blur

So rude you are and manage together with other party faithful members here to chase people off but not me, I stand my ground and it is
clear from you rant that you don't understand or want to understand that a previously agreed transaction state can be
broadcast to the network and can be allowed if the users wallet is not on-line.

I agree with Kogs myself as is my right to do so.

There is a standard mining fee for both opening and closing channels.

Sure mate and it can go from $0.10 like we had a year ago or as high as $55 like we witnessed two months ago, all "standard" I
am sure 

You know you have won the debate when the other sides is left with nothing but insults and won't deal with the points raised

[LtMotioN]

Back to the topic at hand, the replies from pebwindkraft and Kogs are accurate based on my understanding.  The channel does indeed stay open until the timelock ends or the other party closes it manually, but if you're offline for too long, there are some risks if you're dealing with people you don't know and trust not to steal from you.  You certainly don't have to be online 24/7 to make it work, though.  You just have to check it often enough to ensure it's all above board.

Yea that is a bit of a problem with it though, I'm sure they will fix it. But having to manually submit the newer signature to steal the other guys funds back for cheating is not very mass adoption friendly. Other scaling methods will help a lot though at least LN isn't the only thing on the table.

I guess though practically speaking. I would have my spending BTC in my LN wallet, so I can have that on my phone and PC probably. Since this isn't meant for storage it might not be as big a problem as I think.


And no truthfully why should we block Anti Cen ? I know he is a major BCH supporter and comes with the hub arguments and stuff, still everything they say is partially true (not the hub argument I believe). We should always keep a balanced conversation and view on things. It is good to hear the other side talking.

[Anti-Cen]

And no truthfully why should we block Anti Cen ? I know he is a major BCH

No don't block me because lots of my comments like others not of the faith get deleted in this forum (Not many in other forums)
and I get regular bans too but all by the moderator here.

Me is not a BCH fan, slightly into ETH, likes Ripple even if It has lost me money but I am a big fan of NEO but I don't own coins in
that one and all the block-chain clones are heading for the scrap heap because it won't ever scale as implemented by the development
team here.

I'm just one of them people that will not tolerate nazi censorship and I carry a ban as a badge of honor 

[DooMAD]

And no truthfully why should we block Anti Cen ? I know he is a major BCH supporter and comes with the hub arguments and stuff, still everything they say is partially true (not the hub argument I believe). We should always keep a balanced conversation and view on things. It is good to hear the other side talking.

To clarify, I'm not saying Anti-Cen should be blocked, just expressing the growing desire to put them on my own ignore list, but then I remember that it's better if someone is around to set the record straight when they go spreading fairy tales in yet another thread.  If anyone ends up believing what Anti-Cen keeps incessantly repeating, that isn't remotely conducive to helping the wider community understanding how Lightning works and other people could potentially end up grossly misinformed.  I'm happy for different viewpoints to be raised, since I fully accept nothing is perfect and there are definitely compromises involved, since it's not the same trust model we've all grown accustomed to, but outright lies and deliberate misinformation are something else entirely.  The learning curve is steep enough as it is, we don't need trolls making it harder still by sending people in completely the wrong direction, saying you have to pay interest on funds in channels that aren't being actively transacted.  Not only is that categorically untrue, it was wholly unrelated to the original topic to begin with.  Clear and blatant trolling.

Yea that is a bit of a problem with it though, I'm sure they will fix it. But having to manually submit the newer signature to steal the other guys funds back for cheating is not very mass adoption friendly. Other scaling methods will help a lot though at least LN isn't the only thing on the table.

Absolutely, it's all a work in progress.  With so many people working on it, improvements are bound to come over time.  In an ideal world, the software itself would keep tabs on which commitment transaction is most recent and would automatically issue the claim for the entire balance if any attempts are made to spend from old commitments.  It's probable that much of it can be automated, given time and sufficient testing.  Plus there are other things being worked on that should hopefully help as well.  And I suspect those too will be subject to similar misinformation and FUD campaigns by bad actors.  All we moderately savvy end-users can do is continue to confront the chicanery as we find it, while the coders keep up the sterling work.

[pebwindkraft]

...
But having to manually submit the newer signature to steal the other guys funds back for cheating is not very mass adoption friendly. Other scaling methods will help a lot though at least LN isn't the only thing on the table.
...

No, it is not user friendly - but having a screw driver for nails in a wall is also not user friendly. And as Lightning network is a "MICRO PAYMENT CHANNEL", then micro amounts can get lost - based on everyones personal risk appetite... At the point in time, where a lightning channel is opened, both parties sign a smart contract, with pre-defined conditions! So the details are known - it doesn't/shouldn't come as a surprise. So you know what you do...

I think the point is, that Lightning is a micro payment channel. Too new to be fully understood by everyone (and that's probably due to the fact that so many misinterpretations/FUD are around), with a steep learning curve. Hence need to manage expectations. With more and more nodes getting in production (and usecases on top), I am convinced we'll see more and more userfriendly software. I wouldn't want give my money into a smart contract, which is written by noobs in Java Script like language, with many proofs of losses, in the million dollars range. Turing complete and easy to write contracts, but "good" for user friendliness?  - no thanks!
That Lightning baby is barely 3 month on main net now, and expectations are already high? Please, give it a bit more time!

It's a bi-directional payment channel. So e.g. for streaming music, and paying per title, per minute, or even per parts of a minute. In the strong sense, this could be done with a uni directional payment channel. Lightning adds on top the possibility to create a network, where you can rely on others, and if their node goes down, find a new route and continue payments. This makes it fault tolerant.
I want to stress again the micro payments in both directions. Not huge amounts of money, just micro payments. And like in real life, you don't send pennies back and forth. Au contraire, if you go to your grocery shop with a kilo of pennies, they might refuse the payment.
Lightning is certainly not a replacement for your bitcoin wallet - it is an extension. It was repeatedly mentioned, that mostly companies/merchants would run 24/7 LN nodes, and also there is discussion around 3rd parties, which do some kind of watching service, in case one party is offline - (Windows) computers tend to reboot or break sometimes :-(

If it is preferred to have non-mirco payment channels, that become more user friendly, then one could think about uni-directional payment channels. They are already for some years around, and the time-lock based payment channels had to wait for SegWit to lock in (melleability fix), or they had to use CHECKLOCKTIMEVERIFY (CLTV, I think in 2016) or last recently CHECKSEQUENCEVERIFY (CSV). These payment channels allow to create connectivity between a service provider and a host, like publishers or even video (https://streamium.io).

If lightning channels are not needed, or there are no regular payments required, or the personal, specific usecase is unknown, at any time "we" are free to  send normal bitcoin transaction. Preferably a segwit tx ...

[Carlton Banks]

having to manually submit the newer signature to steal the other guys funds back for cheating is not very mass adoption friendly.

Just add this to the long list of computing issues that are best handled by running your own server 24/7

• Want private email? Run your own email server
• Want private social media that you control? Run your own social media server
• Want private internet? Run your own meshnet router
• Want private money? Run your own cryptocurrecy node

Maybe none of that's user friendly, but it's in everyone's interests to either learn to do it, or find someone they know and trust to help them. Letting internet based corporations do these things for you should be looking less and less attractive every day.


Regular adults used to treat all computing as a "nerds only" thing, running private servers will eventually follow that pattern.  

[Kogs]

But having to manually submit the newer signature to steal the other guys funds back for cheating is not very mass adoption friendly.

I'm quite sure you don't need to do this manually. The lightning node software is doing this for you automatically when it identify an unfair player.
But for that you have to be online (at least to be online again before the time lock of your channel partners transaction is reached).

It's correct that you don't need to be online 24/7 as this time lock is quite high. I think 1000 blocks or so, which are roughly 7 days. But I could be wrong with this. Better look up yourself if you want the correct time.

[Carlton Banks]

I'm quite sure you don't need to do this manually. The lightning node software is doing this for you automatically when it identify an unfair player.
But for that you have to be online (at least to be online again before the time lock of your channel partners transaction is reached).

It's correct that you don't need to be online 24/7 as this time lock is quite high. I think 1000 blocks or so, which are roughly 7 days. But I could be wrong with this. Better look up yourself if you want the correct time.

The lightning software will generally be opening channels for you automatically too. This means remembering the expiry points of maybe dozens of locktimes, which won't be practical.

Really, it's better to keep your node up as permanently as possible. This is the "be your own bank" movement, after all.

[DooMAD]

I've just read the lnd 0.4 beta announcement, which hints at future development for what they're calling "Watchtowers".  These should help in situations where users are offline:

Watchtowers and backups - to provide maximum safety for the funds of Lightning users, “watchtowers” will monitor the blockchain for invalid channel transactions. Typically, Lightning nodes need to be online in order to protect against these events, but watchtowers provide this protection for nodes that have intermittent connectivity, e.g. mobile phones. Even for connected nodes, watchtowers can serve as a secondary line of defense in the face of unplanned service outages.

It should be stressed this isn't in the current release, but it supports the notion that developers are fully aware of the issues people are raising about the risks of being offline, so they're working on ways to make things safer.

It's also worth noting, assuming my understanding is correct (but someone please let me know if I'm wrong), that cheating would only be an issue if you are receiving a payment.  If you're sending funds to someone else and they try to "cheat" by settling a previous commitment on the blockchain, they'd be spending from a balance where you had more money and they had less, effectively giving back what you've already sent them.  So I don't think anyone will be silly enough to try that when there's nothing to gain and it means they could also lose their own funds in the process due to revocation.  

[pebwindkraft]

... This is the "be your own bank" movement, after all.

This ! 

concerning 24/7 node and cheating, I found this as well:
(from here: https://bitcoin.stackexchange.com/questions/43700/how-does-the-lightning-network-work-in-simple-terms)

... We each create a new payout transaction ("balance sheet") as before, but this one says that you get 0.06 BTC and I get 0.04 BTC. Each of us gets a transaction signed by the other to that effect as before. To make sure that neither of us can use the old payout transaction the other signed previously, we each create an "anti-cheat" transaction: It's a transaction that spends the outputs from our first payout transaction to the other.

I.e. when I try to activate the (now obsolete) 0.05 - 0.05 BTC balance sheet, my paid-out funds are locked for a number of blocks. This gives you time to broadcast the "anti-cheat" transaction in which I signed that my 0.05 BTC output gets send to you.

Still, it's safe for me to give that transaction to you, and the whole network, because the "anti-cheat" can only be activated as a response to the fraudulent use of an old balance sheet. By the way, this anti-cheat mechanism is why Lightning needs the Transaction Malleability fix from Segregated Witness.
With the setup as described above, I'd have to be online to catch you trying to cheat, but obviously it wouldn't be safe for me to keep payment channels open if I had to remain online all the time. So, to encourage others to help with the "anti-cheat" transaction, we set a small portion of the "anti-cheat" payout as a bounty that anyone can spend. Now, we can entrust the anti-cheat transaction to all nodes on the network, so everyone can watch for old balance-sheets being broadcast. When it happens, anyone can sign the bounty to themselves and broadcast the "anti-cheat".

[LtMotioN]

I've just read the lnd 0.4 beta announcement, which hints at future development for what they're calling "Watchtowers".  These should help in situations where users are offline:

Watchtowers and backups - to provide maximum safety for the funds of Lightning users, “watchtowers” will monitor the blockchain for invalid channel transactions. Typically, Lightning nodes need to be online in order to protect against these events, but watchtowers provide this protection for nodes that have intermittent connectivity, e.g. mobile phones. Even for connected nodes, watchtowers can serve as a secondary line of defense in the face of unplanned service outages.

Good to see they are working on these things, we would be naive to say LN is perfect. But it seems to be getting there to be an amazing solution. I think the real priority lies with wallet providers to ensure these security mechanisms integrate fluently.

Would solutions like a third party watchtower not be centralized though? Or would any participant in LN be able to be a watchtower for the rest of the network?

[DooMAD]

Would solutions like a third party watchtower not be centralized though? Or would any participant in LN be able to be a watchtower for the rest of the network?

Difficult to tell at this early stage.  One would hope it's as decentralised as possible.  Pure guesswork and speculation here, but assuming it does just consist of some code running on an online node to monitor the rest of the network, I can't think of any other prerequisites that would mean it has to be centralised in order to function.  Anyone should, in theory at least, be able to do that if they have a permanent connection.