From 97c8927d666476b60e334c4139dcdf1c1ed22530 Mon Sep 17 00:00:00 2001 From: 8go Date: Wed, 22 Apr 2020 16:40:14 +0000 Subject: [PATCH] improvements to chapter "Commitment Transaction", part 2 (#189) - comma after however - when referring to time "immediately" is better and more meaningful than "directly" - when referring to time duration "lasts" is better than "is" - consistency: "channel partner" better than "party" - etc --- ch03.asciidoc | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/ch03.asciidoc b/ch03.asciidoc index 63e2772..0b9e2df 100644 --- a/ch03.asciidoc +++ b/ch03.asciidoc @@ -205,21 +205,24 @@ A key characteristic of bitcoin is that once a transaction is valid, it remains We will now see how such a penalty mechanism can be included to the above construction of the commitment transactions. Usually the commitment transaction has at least two outputs, one for each partner. -However a channel partner will encumber their own output with a timelock and a revocation secret. -The timelock prevents the owner of the output to spend it directly once the commitment transaction was included in a block. -The timelock is usually measured in blocktime and can be up to 2016 which is statistically speaking two weeks (assuming a blocktime of 10 minutes which is the target for the Bitcoin network). -Within the timelock anyone who knows the revocation secret can spend the output even well before the timelock was over. -Alice and Bob know only one half of the revocation secret but if they share their half with the other party, the other party knows the full secret. +As new addition, a channel partner will encumber their own output with a timelock and a revocation secret. +The timelock prevents the owner of the output to spend it immediately once the commitment transaction was included in a block. +The timelock is usually measured in blocktime and can be up to 2016. +On average, 2016 blocks represent or last two weeks (assuming a blocktime of 10 minutes as in the Bitcoin network). +Within the timelock anyone who knows the revocation secret can spend the output even before the timelock is over. +Alice and Bob know only one half each of the revocation secret. +But if they share their half with the other channel partner, theh the other partner knows the full secret. In order to update the balance and receive a signature from Bob, Alice will have to share her half of the revocation secret of the current commitment transaction with Bob. -Obviously for every new update of the channel balance new revocation secrets have to be created and the old ones all need to be saved. -Luckily the secrets are rather small and it is only the channel partners who need to do that, not the entire network. -Still managing the revocation secrets is one of the more tricky parts of Lightning nodes that hinders node operators to maintain backups. -Watchtower services or switching to the aforementioned eltoo channels might be future strategies to mitigate these problems. +Obviously, for every new update of the channel balance new revocation secrets have to be created and saved. +As long as a channel remains open, all revocation secrets ever created for this specific channel need to be keep as they might be needed in the future. +Luckily, the secrets are rather small and it is only the channel partners who need to keep them, not the entire network. +Nevertheless, managing and storing the revocation secrets is one of the more elaborate parts of Lightning nodes that require node operators to maintain backups. +Other technologies such as Watchtower services or switching to the aforementioned "eltoo" channels might be future strategies to mitigate these issues. -With the timelocks in place Alice can close the channel at any time if Bob does not respond. -She has to wait for the time lock until she can spend her funds from the commitment transaction after the commitment transaction has a confirmation. -Other than that and the fees for opening and closing a channel there comes no additional burden with maintaining a payment channel. +With the timelocks in place Alice can close the channel at any time if Bob does not respond, claiming her fair share of the balance. +After publishing the commitment transaction "on-chain" Alice has to wait for the time lock to expire before she can spend her funds from the commitment transaction. +Other than that and the "on-chain" fees for opening and closing a channel there comes no additional burden with maintaining a payment channel. ==== Announcing the channel Channel partners can agree to publicly announce the channel over the gossip protocol that comes with the Lightning Network.