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@hrkrshnn
hrkrshnn / generic.org
Last active March 19, 2025 23:52
Some generic writeup about common gas optimizations, etc.

Upgrade to at least 0.8.4

Using newer compiler versions and the optimizer gives gas optimizations and additional safety checks for free!

The advantages of versions 0.8.* over <0.8.0 are:

  • Safemath by default from 0.8.0 (can be more gas efficient than some library based safemath).
  • Low level inliner from 0.8.2, leads to cheaper runtime gas. Especially relevant when the contract has small functions. For
@patrickd-
patrickd- / cheatsheet.md
Last active March 20, 2024 23:13
Solidity – Compilable Cheatsheet
@0xkarmacoma
0xkarmacoma / sending-ether-cheat-sheet.md
Last active May 1, 2025 03:17
Sending Ether Cheat Sheet

Sending Ether Cheat Sheet

TLDR

🥇 Instead of sending Ether, use the withdrawal pattern

🥈 If you really need to send Ether, use a safe wrapper like OpenZeppelin's Address.sendValue(addr, amount)

🥉 If you really need to send Ether without dependencies, use (bool success, ) = addr.call{value: amount}("")

@HildisviniOttar
HildisviniOttar / thorchain_vulnerability_tss.md
Last active November 13, 2021 19:20
THORChain vulnerability TSS

TSS Churn with 2 evil nodes

Currently TSS works by the system auto-generating a set of TSS invitees that collectively generate a new vault pubkey outside of process. Each node that participates in the signing ceremony then posts in their results into THORChain as a MsgTssPool.

Two evil nodes are able to front-run a TSS signing ceremony by posting in a fake TSS result and voting twice, which achieves consensus and creates a vault controlled by attacker, stealing funds (before the valid tx arrives).

Note: #thorsec team found a similar bug allowing spoofing ID which was patched in https://gitlab.com/thorchain/thornode/-/merge_requests/1922 - this vulnerability is similar but works even with the original ID spoof patch. After disclosure, MR 1922 also incorporated fixes to stop this attack presented below.

Difficulty

@shazow
shazow / flashbotnfts.ts
Last active May 26, 2023 01:20
WIP: Flashbot NFTs
import { BigNumber, providers, Wallet } from "https://esm.sh/ethers";
import { FlashbotsBundleProvider, FlashbotsBundleResolution } from "https://esm.sh/@flashbots/ethers-provider-bundle";
const FLASHBOTS_AUTH_KEY = Deno.env.get('FLASHBOTS_AUTH_KEY');
const WALLET_PRIVATE_KEY = Deno.env.get('WALLET_PRIVATE_KEY');
const GWEI = BigNumber.from(10).pow(9);
const PRIORITY_FEE = GWEI.mul(3);
const LEGACY_GAS_PRICE = GWEI.mul(12);
const BLOCKS_IN_THE_FUTURE = 2;
# Ethereum helper methods
# source this in your .bashrc or .zshrc file with `. ~/.ethrc`
# --- Solidity sandbox ---
# https://github.com/maurelian/solidity-sandbox
scratch() {
dir=$(pwd)
cd ~/Documents/projects/solidity-sandbox || exit
bash newTest.sh $1
cd "$dir" || exit
@Strernd
Strernd / parseErc20Transfer.js
Created June 7, 2021 11:09
Parses an ERC20 Transfer from the Ethereum API.
const converter = require("hex2dec");
const Eth = require("ethjs");
const eth = new Eth(new Eth.HttpProvider(process.env.INFURA));
async function getERC20TransferByHash(hash) {
const ethTxData = await eth.getTransactionByHash(hash);
if (ethTxData === null) throw "TX NOT FOUND";
if (
ethTxData.input.length !== 138 ||
ethTxData.input.slice(2, 10) !== "a9059cbb"
@itzmeanjan
itzmeanjan / catch.py
Last active May 28, 2021 21:57
Polygon ( aka Matic Network ) Mempool Exploration
#!/usr/bin/python3
from python_graphql_client import GraphqlClient
from json import dumps
from asyncio import run
from re import compile as re_compile
from pytimeparse import parse
reg = re_compile(r'^(\d+(\.\d+)?)')
handle = None
@gorgos
gorgos / ExampleSlidingWindowOracleDaiWethKovan.sol
Created January 9, 2021 20:16
ExampleSlidingWindowOracle with DAI + WETH for Kovan.
pragma solidity 0.6.6;
pragma experimental ABIEncoderV2;
import "https://github.com/Uniswap/uniswap-v2-core/blob/master/contracts/interfaces/IUniswapV2Pair.sol";
import "https://github.com/Uniswap/uniswap-lib/blob/master/contracts/libraries/FixedPoint.sol";
import "https://github.com/Uniswap/uniswap-lib/blob/master/contracts/libraries/FullMath.sol";
import "https://github.com/Uniswap/uniswap-lib/blob/master/contracts/libraries/Babylonian.sol";
import "https://github.com/Uniswap/uniswap-lib/blob/master/contracts/libraries/BitMath.sol";
library SafeMath {
set-option -g prefix C-g
unbind-key C-g
bind-key C-g send-prefix
set -g default-terminal "screen-256color"
set -ga terminal-overrides ",*256col*:Tc"
set-option -g status-position bottom
set -g base-index 1