Lightining network Watch Towers, Trampoline Routing, Rendevouz Rounting, Huddle Invoices, Turbo Channels and Submarine Payments

Watchtowers one of the most exciting and useful features that are being worked on for the Lightning Network there seem to be a lot of different upgrades to the Lightning Network being proposed such as for example Watchtower as an example is one of the things that we've seen being introduced into the Lightning Network, and what towers are basically they are a third party service that you can subscribe to, that protects your channels when you're offline, the problem in the first iteration of the Lightning Network due to the way in which the channels are constructed, it is possible to broadcast the prior state which means a different mix of local versus remote balance, that would disadvantage one of the parties in the channel, basically what that means is when you sent some money to harold for example over your both common payment channel, and you want that to never happen is that the state of the channel before you sent that money showed more balance on your sides which is advantageous to you, that state should be invalidated when you send the new state to Harold, but you can cheat by sending the old state in the norm protocol if you do that, harold has a period of time in which he can punish you by sending a penalty transaction out that not only gets the state back to the correct state but actually takes away your balance, to punish you which means that you lose all of the money in the channel, and if you try to cheat by keeping more of the balance now that penalty transaction has to be broadcast within a period of time and if harold is offline you can cheat or he is offline and as a result keep a bigger percentage of the balance and close the channel to prevent that harold has to be online all the time, solution with watch towers harold can outsource that, he can say watch this channel and if someone tries to broadcast the prior state please punish them on my behalf, by broadcasting this penalty transaction, watchtower can charge a fee for that and their services that are operated according to a new standard that is implemented than the number of the clients on the Lightning Network, so that's one development a couple of others is Trampoline Routing is an interesting one so this is where instead of your client, your lightening wallets needing to know how to construct a route that connects the payment channels that you have and then further payment channels that gets to a recipient somewhere out there on the Lightning Network, instead you outsource that function to an intermediary node called the trampoline nodes and it's called the trampoline nodes because essentially what you do is you bounce the payments off that trampoline node and the trampoline node does the routing from there, so all you need to know how to route to that trampoline node, it doesn't have to be a node that you have a payment channel to, it could be several hops down but you only need to know the routes to that trampoline node, and then the trampoline node finds the routes to your recipients, this is a great service because that means you can now run a lightweight lightning wallet let's say on mobile device, that does a keep a full map of the channels that are available on the entire Lightning Network in order to construct routes, instead it relies on the trampoline nodes to keep a full map and therefore find routes and that makes things a lot easier, but of course there are some downsides that's because the trampoline node gets a construct route it has the ability to deny service to you or sensor, unless you use another lightning trampoline node and it also leads to a small reduction in privacy because the trampoline node knows the ultimate destination, another mechanism for routing is Rendezvous Routing where the recipient of a lightning payment tells you to route the payments to a specific node that isn't that node effectively a node further away, and then uses either private channels that are not advertised or another route that it communicates the rendezvous node to route it, for the final few hops now think about it for a bit the advantage of that is that you can increase the privacy by hiding behind an intermediary nodes, and using private unpublished channels to routes the last few hops and you can combine the techniques we just talked about, so you could use trampoline and rendezvous theoretically to have the trampoline node routes to a rendezvous node from where the routing is hidden to the final destination take back some of your privacy, Huddle Invoices are another very interesting innovation are invoices that do not expire and where the payment doesn't have to be claimed immediately instead the payment is established, but then held for a while and the recipient nodes can leave it so you can do a number of interesting tricks if you have that kind of delayed payments with huddle invoices, another interesting one is Turbo Channels or using push to push balance when you open a channel in the first place, so this is a way to send money to a node without receiving an invoice and it's also a way to establish inbound liquidity for your own lightning nodes for a fee, so in this case what you do is let's say you wanted to send money to Carol and Carol has not given you an invoice, you can open a channel to Carol and push an amount so that when the channel is initialized some of the money is actually on her end of the channel as her balance from the very beginning and effectively you paid her that money by establishing that channel and you can also do that with the service provider that can open a channel to you to create embalm liquidity and also push some of that as a payment to you you can use a number of other tricks like that another interesting development is development the Submarines Swaps or submarine payments and this is where you do an on chain transaction to a Bitcoin address that also funds a lightning channel so pay this Bitcoin address so I can open a channel or the opposite pay this lightning payment so you can make an on chain Bitcoin transactions so this is effectively an atomic swap between on chain and off chain payments so that they can occur atomically and trustless and so you can move money essentially from on to off chain or from off chain to on chain these are just some of the developments and these are just other things that have emerged to fulfill specific needs and reduce complexity and the use of the Lightning Network just over the last year and a half in its development and these developments are coming very very fast from all corners of the developer ecosystem and lightning