A proposed update mechanism for Layer 2 protocols that uses sequence numbers to enforce the latest agreed upon state.
Questions tagged [eltoo]
17 questions
13
votes
1 answer
Does eltoo require trusting watchtowers not to close channels?
The way Lightning Network works now, watchtowers maintain a list of penalty transactions to broadcast in case one party attempts to close a channel with an outdated channel state. The watchtower cannot on its own initiate the closing of a…
Vojtěch Strnad
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10
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How to emulate SIGHASH_NOINPUT using CHECKSIGFROMSTACKVERIFY?
I read on bitcoin-dev that CHECKSIGFROMSTACKVERIFY (CHECKDATASIG in BCash) can be used to emulate new sighash flags. How would that work, concretely? As an example, please provide an example update transaction based on figure 4 of the Eltoo paper,…
Janus Troelsen
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8
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1 answer
Why aren't 3 party (or more) channels realistically possible in lightning today?
Speaking with Ben on twitter it appears that it isn't feasible without eltoo to create more than 2 party channels on the lightning network today. Why exactly is that the case today and how does eltoo solve it?
arshbot
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6
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3 answers
Eltoo: Does the relative locktime on the first UTXO set the lifetime of the channel?
When we open a lightning channel using eltoo / LN symmetry (standard 2/2 multisig), the setup/funding transaction must be recorded on-chain in order to prevent a "double spend" of the funding inputs (and effectively stealing the channel…
sutterseba
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5
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1 answer
BIP118 (SIGHASH_NOINPUT) vs. ANYPREVOUT
I understand the motivation for SIGHASH_NOINPUT - it would help with offchain payment channels. It was proposed already in the Lightning paper but Eltoo will effectively work just with something like that. But what exactly is the ANYPREVOUT BIP…
fiction
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5
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Lightning Network: asymmetry in the information tracked by each participant?
In following paper, written by Christian Decker et al., there is a paragraph that is not clear to me.
eltoo: A Simple Layer2 Protocol for Bitcoin
"The central idea of Lightning is to invalidate an old state by
punishing the participant…
Questioner
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5
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2 answers
How would an adversary increase the required fee to replace a transaction by up to 500 times?
In the ephemeral anchors draft BIP (also discussed here) it states that without V3 transactions an adversary can increase the required fees to replace a transaction as much as 500 times. That sounds a lot. What is the exact scenario where there…
Michael Folkson
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3
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What is an ephemeral anchor and what problems do they address?
What is an ephemeral anchor and what problem(s) would their introduction address? What is their relation to anchor outputs in Lightning? Are ephemeral anchors a prerequisite for eltoo?
V3 and package RBF are discussed here.
Mailing list post…
Michael Folkson
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3
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2 answers
How do eltoo channel constructions using ANYPREVOUT compare to those using CTV and CSFS?
SIGHASH_ANYPREVOUT has been designed as I understand primarily for the eltoo channel construction use case although it has many other potential use cases too.
BIP 119 states:
Were both OP_CHECKTEMPLATEVERIFY and OP_CHECKSIGFROMSTACKVERIFY to…
Michael Folkson
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3
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1 answer
Is eltoo more memory efficient for watchtowers?
I vaguely remember a paper which stated that in their current implementation, lightning watchtowers require a lot of memory because they need to store information about (a penalty TX for) every balance change that happens on a channel they watch.…
Hare Brained Brian
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2
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Eltoo channel - can opening be off-chain
In Eltoo the set-up phase is similar to Lightning. You fund a n-of-n multisig (usually 2-of-2). Of course you don't want to publish this until you have a bail-out possibility - called "settlement transaction" here.
But what I found out is this…
fiction
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2
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2 answers
Does Eltoo eliminate the need to watch the blockchain/implement Watchtowers
Reading Blockstream's introduction article on Eltoo and one paragraph says:
[..] in eltoo all participants share a common set of transactions, unlike LN-penalty, which requires asymmetry in which participant has access to which transactions, in…
user82756
2
votes
1 answer
What are the pitfalls of repurposing the nLocktime field for backward compatability in eltoo?
In the eltoo proposal for paymentchannel management with less overhead proposed by Christian Decker et al. the update transactions need to be ordered. In chapter 4.1.2 of the proposal it is described for the sake of being backwards compatible that…
Rene Pickhardt
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Why does the funder send the signed settlement to the counter-party in eltoo?
Quoting from the Eltoo paper:
Before signing and broadcasting the funding transaction the funder requires the other endpoint to create an initial settlement transaction that
returns the funds back to the funder. The initial settlement…
Andrej Mitrović
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Are both CSV and nLocktime unnecessary in Eltoo?
The Eltoo paper says "Notice that we could use nSequence for this purpose, but due to the interplay with OP_CSV we opted to use nLocktime". Now that Lau showed CSV not to be necessary, does that mean that there is also no reason to use nLocktime?
Janus Troelsen
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