5 votes
Accepted

Lightning Network: asymmetry in the information tracked by each participant?

When two channel participants open a channel or update it, they exchange commitment transactions. These commitment transactions allow each party to unilaterally close the channel. The commitment ...
Murch's user avatar
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3 votes
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What is a payment basepoint?

Basepoints are simply public keys from which all other public keys for a certain category (payments, revocation, htlcs, ..) are derived. They are used in order to deterministically generate fresh keys ...
Antoine Poinsot's user avatar
3 votes

Why would a transaction have a locktime of 1987!

You are looking at a Commitment Transaction. Commitment transactions are submitted to the network by one channel owner to unilaterally close a Lightning Network channel. The locktime in commitment ...
Murch's user avatar
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3 votes

Cheat Lightning network (c-lightning)

c-lightning doesn't store old versions of the commitment transaction, exactly in order to avoid accidentally cheating. If you compiled with DEVELOPER=1 you can however call lightning-cli dev-sign-last-...
cdecker's user avatar
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3 votes
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Why does every HTLC in a commitment transaction require its own signature?

Why isn't the signature for the entire commitment transaction enough? Because the htlc_signature field contains the signature for the HTLC transactions spending from the htlc output(s) (either ...
Antoine Poinsot's user avatar
3 votes
Accepted

What is the relation between a Hash Time Lock Contract(HTLC) and a Commitment transaction?

When a HTLC is created, a new commitment transaction is created. The HTLC is an additional output (script) in this new commitment transaction, in addition to the RSMC and “regular” outputs, and ...
James C.'s user avatar
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3 votes

Order of Exchanging Revocation Keys during Lightning Transactions

Alice and Bob jointly create a public key R for each revocable output (RSMC output script). They each privately generate r-1 and r-2, and derive public keys R-1 and R-2 from these. R is the sum of R-...
James C.'s user avatar
  • 2,511
3 votes
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Lightning Network: what happens if parties lose their txs?

Yes that is correct. Bob's revocation secret is used as an insurance policy for Alice. If she loses it, Bob will be able to act maliciously and get away with it. However, I want to add two things: ...
Rene Pickhardt's user avatar
3 votes

What is the input and output script of the funding transaction?

What is the script of the output script of the state block (the block that starts the channel)? The output script of the funding transaction is a P2WSH output where the witness script is a 2-of-2 ...
Ava Chow's user avatar
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3 votes
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In Lightning commitment transactions, what do the upper 8 bits of sequence and locktime represent?

If you look at git blame of BOLT 03 you can track the sentence regarding the locktime down to this commit: https://github.com/lightningnetwork/lightning-rfc/commit/...
Rene Pickhardt's user avatar
2 votes

Why do we use CLTV instead of CSV in the HTLC output of the commitment transaction?

As you have said yourself, CSV is relative to when the transaction appears in the blockchain, while CLTV is absolute. They just have different meanings, which are useful for different things: The ...
stefanwouldgo's user avatar
2 votes
Accepted

Why do we use CLTV instead of CSV in the HTLC output of the commitment transaction?

When creating a commitment transaction, you consume the multi-sig output of the funding transaction as the input. CSV is a relative timelock opcode which means the time specified in the CSV is a ...
Ugam Kamat's user avatar
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2 votes
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What happens if the commitment tx fee is too low?

Only if the state changes fees are negotiated (and for mutual closing the channel) so in case the onchain fees change and the channel is not used for a long time just send a fake payment hash to adapt ...
Rene Pickhardt's user avatar
2 votes
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Lightning Network: hashlocks vs private keys exchange

So the question is: are commitment transactions between two nodes revoked through hashlocks or through private keys exchange? Either way will work, but hashlocks are simpler. They're described in ...
Nick ODell's user avatar
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1 vote
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Using multiple penalty transactions to increase max HTLCs per LN channel

Are there any significant hurdles preventing us from using multiple penalty transactions, where the nth penalty transaction spends HTLCs [n*483; (n+1)*483[ from the commitment transaction? At first ...
David A. Harding's user avatar
1 vote
Accepted

Lightning - why are commitment transactions supposed to use different keys

An optimization is to use elliptic curve trickery and thus construct something similar to pay2contract scheme. I believe this way you still have to store all old values or am I mistaken? The elliptic ...
yyforyongyu's user avatar
1 vote
Accepted

Could someone provide an example of a tx spending from an input with a relative LockTime?

If you look at https://blockstream.info/address/bc1qdv0fk4c73fem89s708pzdny8q25d7k5nrckckp87c8alwaw803fq3mqrpz you will see that there are two transactions. The first one https://blockstream.info/...
Rene Pickhardt's user avatar
1 vote
Accepted

How are transactions invalidated by nodes when both parties are offline in a Lightning Network?

AFAIU, if you have open lightning channels, you cannot go offline. You must be online in order to monitor the blockchain for old commitments. If you see an old commitment transaction, you immediately ...
Ava Chow's user avatar
  • 70.1k

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