metacoin

Alexandria

Keeping History Honest

Joseph Fiscella

joseph@blocktech.com

Introduction

taariq

Hi all,

Tadge Dryja's Discreet Log Contracts (DLC) can be combined with Andrew Poelstra's Adaptor Signatures (AS). I'm simply describing the combination of the two existing concepts without any fundamental changes, but I thought it was worth writing out explicitly since I haven't seen any write-up. Hopefully it doesn't contain any errors.

Starting from Schnorr signature [R, s].

In DLC, the oracle will reveal one of multiple possible s values as part of signing the outcome of an event. This s is essentially a private key for which the public key S can be calculated ahead of time (because R is committed to in advance).

In AS, instead of just R (essentially a public key), you add a second public key P of which the payer wishes to obtain the private key p from the payee. Only by revealing p can the payee make the signature valid, and thus receive the payment.

elichai

cmake_minimum_required(VERSION 2.8.4)
project(bitcoin)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")

file(GLOB_RECURSE SOURCES_FILES CONFIGURE_DEPENDS src/*.cpp src/*.c src/*.h)

include_directories(SYSTEM src
        src/bench
        src/compat

jachiang

from test_framework.test_framework import BitcoinTestFramework
from test_framework.address import program_to_witness
from test_framework.script import CScript, TaprootSignatureHash, taproot_construct
from test_framework.script import OP_DUP, OP_HASH160, OP_EQUALVERIFY, OP_CHECKSIG
from test_framework.messages import CTxInWitness, CScriptWitness, COutPoint, CTxIn, CTxOut, CTransaction, sha256 
from test_framework.util import hex_str_to_bytes
from test_framework.key import ECKey

import hashlib 
from io import BytesIO

t-bast

Route Blinding

Notations

• Alice's real node_id is P_a = k_a * G
• Bob's real node_id is P_b = k_b * G
• Alice's blinded node_id is D_a = d_a * G
• Bob's blinded node_id is D_b = d_b * G
• Alice <-> Bob real short_channel_id is scid_ab
• Alice <-> Bob blinded short_channel_id is blinded_scid_ab

remyers

                                                                                         
  [Fund Channel]                                                                         
    |                                                                                    
    |                                                                                    
    |                                                                                    
    v                                                                                    
   P=Musig(A,B)+scripts (for Taproot script-path spend)                                  
   Q=Musig(A,B) (for Taproot key-path spend)                                             
                                                                                         
   OR ----------- [Cooperative Close]                                                    

asoltys

lightning

#!/bin/bash
export PATH=$PATH:/home/adam/data/openwrt/staging_dir/toolchain-arm_cortex-a9+vfpv3_gcc-8.3.0_musl_eabi/bin
export STAGING_DIR=/home/adam/data/openwrt/staging_dir/toolchain-arm_cortex-a9+vfpv3_gcc-8.3.0_musl_eabi
export target_host=arm-openwrt-linux-muslgnueabi
export AR=$target_host-ar
export AS=$target_host-as
export CC=$target_host-gcc
export CXX=$target_host-g++

fjahr

Rolling UTXO Set Hash proposal

TL;DR

I have picked up Pieter Wuille's proposal from 2017 to use a rolling hash for the UTXO set hash. It deals with the problem of a long computation time of the UTXO set hash which results in a slow RPC call gettxoutsetinfo (can take several minutes depending on hardware). I investigated three hash functions: MuHash, ECMH and LtHash and started implementing them in Bitcoin Core for comparison. However only MuHash has a rolling hash implementation

jachiang

from test_framework.test_framework import BitcoinTestFramework
from test_framework.address import program_to_witness
from test_framework.script import CScriptOp, CScript, TaprootSignatureHash, taproot_construct
from test_framework.script import OP_DUP, OP_HASH160, OP_EQUAL, OP_EQUALVERIFY, OP_CHECKSIG, OP_CHECKSIGADD
from test_framework.messages import CTxInWitness, CScriptWitness, COutPoint, CTxIn, CTxOut, CTransaction, sha256 
from test_framework.util import hex_str_to_bytes

from test_framework.key import ECKey
import hashlib 
import itertools 

roconnor-blockstream

{
  "txid": "0e8e133dd88282a4f64919e046027d3b40a572c32d0ce6b646a403bed0d51750",
  "hash": "0e8e133dd88282a4f64919e046027d3b40a572c32d0ce6b646a403bed0d51750",
  "wtxid": "0e8e133dd88282a4f64919e046027d3b40a572c32d0ce6b646a403bed0d51750",
  "withash": "ab3393f4fb64685a4de07ac89c6903d6a0ba107c87fff33c9a981a7590bae48e",
  "version": 2,
  "size": 240,
  "vsize": 240,
  "weight": 960,
  "locktime": 0,