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@markblundeberg
markblundeberg / covenant_noinput.md
Last active February 5, 2021 20:05
BCH floating transactions: SIGHASH_NOINPUT emulation using CHECKDATASIG covenants

BCH floating transactions: SIGHASH_NOINPUT emulation using CHECKDATASIG covenants

A new sighash flag has been proposed (originally for Lightning, now for Eltoo) which redacts information about the spending inputs, most notably their transaction IDs.

This facility is both powerful and dangerous: it means that signatures intended for one transaction can be used on other transactions. It also makes up a very strong increase in the malleability of transactions. SIGHASH_NOINPUT allows for much more flexible off-chain smart contracts than nonmalleable transactions. Note that Eltoo requires SIGHASH_NOINPUT, for instance. It's not clear whether such a dangerous feature will be adopted on BCH any time soon.

In this gist I'm going to explain that CHECKDATASIG covenants let us write smart contracts that emulate SIGHASH_NOINPUT. This capability alone should in principle allow to build Lightning, Eltoo with bilaterally funded smart contracts on BCH (though, with some significant

@phillipi
phillipi / biggan_slerp
Last active October 8, 2023 01:25
Slerp through the BigGAN latent space
# to be used in conjunction with the functions defined here:
# https://colab.research.google.com/github/tensorflow/hub/blob/master/examples/colab/biggan_generation_with_tf_hub.ipynb
# party parrot transformation
noise_seed_A = 3 # right facing
noise_seed_B = 31 # left facing
num_interps = 14
truncation = 0.2
category = 14
@5chdn
5chdn / stureby.aleth.json
Last active December 3, 2018 21:51
Stureby PoW Testnet Configuration for Constantinople Transition
{
"sealEngine":"Ethash",
"params":{
"accountStartNonce":"0x00",
"maximumExtraDataSize":"0x20",
"homesteadForkBlock":"0x2710",
"daoHardforkBlock":"0x00",
"EIP150ForkBlock":"0x3a98",
"EIP158ForkBlock":"0x59d8",
"byzantiumForkBlock":"0x7530",
@Haseeb-Qureshi
Haseeb-Qureshi / snargs.md
Created October 10, 2018 19:51
Transaprent Succinct Arguments @ CESC

Transparent Succinct Arguments

Alessandro Chiesa (UC Berkeley, Starkware, Zcash)

What are succinct arguments?

  • Proofs of computational integrity
  • Game between prover and verifier
  • Prover knows an input to a F(x) that would make it return y
  • Prover could trivially prove this by providing x
    • This convinces the verifier for sure!
  • Being able to convince the verifier of a true claim is the property of completeness
@yaronvel
yaronvel / PizzaStore.sol
Last active December 6, 2018 09:59
pragma solidity ^0.4.24;
contract PizzaStore {
uint constant SLICE_PRICE_IN_ETH = 1e17;
uint constant SLICE_PRICE_IN_TOKEN = 1e19;
ERC20Interface constant PIZZA_TOKEN = ERC20Interface(0xdd974D5C2e2928deA5F71b9825b8b646686BD200);
event ProofOfPayment(address _beneficiary, address _token, uint _amount, bytes32 _data);
@BjornvdLaan
BjornvdLaan / BLSExample.sol
Last active April 10, 2023 07:49
Verification of BLS signatures and BGLS aggregate signatures in Ethereum
pragma solidity ^0.4.14;
/*
Example of how to verify BLS signatures and BGLS aggregate signatures in Ethereum.
Signatures are generated using https://github.com/Project-Arda/bgls
Code is based on https://github.com/jstoxrocky/zksnarks_example
*/
contract BLSExample {
@gnidan
gnidan / allocation-storage.md
Last active April 2, 2025 20:08
solidity allocation examples

storing things with solidity for fun and confusion

uint64[] with 9 elements

storing [ 10, 11, 12, 13, 14, 15, 16, 17, 18 ]:

   ...
@Arachnid
Arachnid / OpcodeChecker.sol
Last active October 19, 2018 19:02
/**
* @dev OpcodeChecker processes contract code to generate a bitmap of used opcodes.
*
* DO NOT USE: See the vulnerability identified by Recmo below. A patch will be provided soon.
*
* The generated bitmap can be used to enforce whitelisting and blacklisting on contract code.
* Bit n of the bitmap is set iff opcode n is used. For instance, the presence of the STOP opcode
* will result in bit 0 of the bitmap being set.
*
* A best-effort attempt is made to skip over unreachable data, but there may be false positives.
@amiller
amiller / TinyDuplex.sol
Last active May 13, 2019 20:38
TinyDuplex.sol: minimalist duplex micropayment channel for Ethereum
pragma solidity ^0.4.22;
// ECE 398 SC - Smart Contracts and Blockchain Security
// http://soc1024.ece.illinois.edu/teaching/ece398sc/spring2018/
// Simpest possible duplex-micropayment channel
// - Funded with an up front amount at initialization
// - The contract creator is called "alice". The other party, "bob", is passed
// as an argument to the Constructor
// - There is no fixed deadline, but instead any party can initiate a dispute,
// which lasts for a fixed time
@dylanmckay
dylanmckay / facebook-contact-info-summary.rb
Last active July 3, 2025 21:22
A Ruby script for collecting phone record statistics from a Facebook user data dump
#! /usr/bin/env ruby
# NOTE: Requires Ruby 2.1 or greater.
# This script can be used to parse and dump the information from
# the 'html/contact_info.htm' file in a Facebook user data ZIP download.
#
# It prints all cell phone call + SMS message + MMS records, plus a summary of each.
#
# It also dumps all of the records into CSV files inside a 'CSV' folder, that is created