Scripts

Each participant has its own anchor output that locks to their funding key. This allows using CPFP carve-out (see https://github.com/bitcoin/bitcoin/pull/15681) to speed up confirmation of a commitment transaction.

This function interprets the locktime for the given transaction, and returns the block height before which this tx cannot be published. By convention in bitcoin, depending of the value of locktime it might be a number of blocks or a number of seconds since epoch. This function does not support the case when the locktime is a number of seconds that is not way in the past. NB: We use this property in lightning to store data in this field.

Convert a raw ECDSA signature (r,s) to a der-encoded signature that can be used in bitcoin scripts.

minimal encoding of a number into a script element:

• OP_0 to OP_16 if 0 <= n <= 16
• OP_PUSHDATA(encodeNumber(n)) otherwise

Extract the payment hash from a timed-out received htlc.

Extract the payment hash from a 2nd-stage HTLC Timeout transaction's witness script

Extract the payment preimage from from a fulfilled offered htlc.

Extract the payment preimage from a 2nd-stage HTLC Success transaction's witness script

With the anchor outputs format, the to_remote output is delayed with a CSV 1 to allow CPFP carve-out on anchors.

This witness script spends a local anchor output using a local sig.

This witness script spends either a local or remote anchor output after its CSV delay.

If remote publishes its commit tx where there was a remote->local htlc, then local uses this script to claim its funds using a payment preimage (consumes htlcOffered script from commit tx)

If remote publishes its commit tx where there was a local->remote htlc, then local uses this script to claim its funds after timeout (consumes htlcReceived script from commit tx)

If remote publishes its commit tx where there was a to_remote delayed output (anchor outputs format), then local uses this script to claim its funds (consumes to_remote script from commit tx).

This is the witness script of the 2nd-stage HTLC Success transaction (consumes htlcOffered script from commit tx)

This is the witness script of the 2nd-stage HTLC Timeout transaction (consumes htlcOffered script from commit tx)

This witness script spends (steals) a htlcOffered or htlcReceived output using a revocation key as a punishment for having published a revoked transaction

This witness script spends a toLocalDelayed output using a local sig after a delay

This witness script spends (steals) a toLocalDelayed output using a revocation key as a punishment for having published a revoked transaction