tlnbase: verify their htlc signature - electrum - Electrum Bitcoin wallet
 (HTM) git clone https://git.parazyd.org/electrum
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       ---
 (DIR) commit 309aca69b848a2fbdd14098213a13a53151413f0
 (DIR) parent 6b79052bc9710f9c96634b76f918fb6a040e19c2
 (HTM) Author: Janus <ysangkok@gmail.com>
       Date:   Wed,  2 May 2018 17:01:35 +0200
       
       lnbase: verify their htlc signature
       
       Diffstat:
         M lib/lnbase.py                       |      29 ++++++++++++++++++++++++++---
       
       1 file changed, 26 insertions(+), 3 deletions(-)
       ---
 (DIR) diff --git a/lib/lnbase.py b/lib/lnbase.py
       t@@ -948,7 +948,31 @@ class Peer(PrintError):
                if htlc_sigs_len != 64:
                    raise Exception("unexpected number of htlc signatures: " + str(htlc_sigs_len))
        
       -        # TODO verify htlc_signature
       +        local_last_per_commitment_secret = get_per_commitment_secret_from_seed(local_per_commitment_secret_seed, 2**48-2)
       +        local_last_per_commitment_point = secret_to_pubkey(int.from_bytes(
       +            local_last_per_commitment_secret,
       +            byteorder="big"))
       +        revocation_pubkey = derive_blinded_pubkey(chan.remote_config.revocation_basepoint.pubkey, local_last_per_commitment_point)
       +        remote_delayedpubkey = derive_pubkey(chan.local_config.delayed_basepoint.pubkey, local_last_per_commitment_point)
       +        htlc_tx_output = make_htlc_tx_output(
       +            amount_msat = amount_msat,
       +            local_feerate = chan.constraints.feerate,
       +            revocationpubkey=revocation_pubkey,
       +            local_delayedpubkey=remote_delayedpubkey,
       +            success = True, # HTLC-success for the HTLC spending from a received HTLC output
       +            to_self_delay = chan.remote_config.to_self_delay)
       +        preimage_script = htlcs_in_local[0][0]
       +        htlc_tx_inputs = make_htlc_tx_inputs(
       +            new_commitment.txid(), new_commitment.htlc_output_indices[0],
       +            revocationpubkey=revocation_pubkey,
       +            local_delayedpubkey=remote_delayedpubkey,
       +            amount_msat=amount_msat,
       +            witness_script=bh2u(preimage_script))
       +        htlc_tx = make_htlc_tx(0, inputs=htlc_tx_inputs, output=htlc_tx_output)
       +        print("htlc tx preimage", htlc_tx.serialize_preimage(0))
       +        pre_hash = bitcoin.Hash(bfh(htlc_tx.serialize_preimage(0)))
       +        remote_htlc_pubkey = derive_pubkey(chan.remote_config.htlc_basepoint.pubkey, local_last_per_commitment_point)
       +        assert bitcoin.verify_signature(remote_htlc_pubkey, commitment_signed_msg["htlc_signature"], pre_hash)
        
                local_last_pcs_index = 2**48 - chan.local_state.ctn - 1
                local_last_per_commitment_secret = get_per_commitment_secret_from_seed(local_per_commitment_secret_seed, local_last_pcs_index)
       t@@ -985,7 +1009,6 @@ class Peer(PrintError):
                    success = False, # timeout for the one offering an HTLC
                    to_self_delay = chan.local_config.to_self_delay)
                preimage_script = htlcs_in_remote[0][0]
       -        htlc_output_txid = remote_ctx.txid()
                htlc_tx_inputs = make_htlc_tx_inputs(
                    remote_ctx.txid(), remote_ctx.htlc_output_indices[0],
                    revocationpubkey=revocation_pubkey,
       t@@ -1068,7 +1091,7 @@ class Peer(PrintError):
        class LNWorker:
        
            def __init__(self, wallet, network):
       -        self.privkey = bitcoin.sha256('1234567890')
       +        self.privkey = H256(str(time.time()).encode("ascii"))
                self.wallet = wallet
                self.network = network
                self.config = network.config