This document describes a simple contract in pseudocode and gives a couple of test cases for it.
The challenge is designed to be fairly easy to implement in a language of choice, compiled to wasm and interacted with. It is loosely based on the ERC20 token standard, named "WRC20", where the W stands for WebAssembly.
The contract has two features:
| 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 |
| /*** | |
| * Shoutouts: | |
| * | |
| * Bytecode origin https://www.reddit.com/r/ethereum/comments/6ic49q/any_assembly_programmers_willing_to_write_a/dj5ceuw/ | |
| * Modified version of Vitalik's https://www.reddit.com/r/ethereum/comments/6c1jui/delegatecall_forwarders_how_to_save_5098_on/ | |
| * Credits to Jorge Izquierdo (@izqui) for coming up with this design here: https://gist.github.com/izqui/7f904443e6d19c1ab52ec7f5ad46b3a8 | |
| * Credits to Stefan George (@Georgi87) for inspiration for many of the improvements from Gnosis Safe: https://github.com/gnosis/gnosis-safe-contracts | |
| * | |
| * This version has many improvements over the original @izqui's library like using REVERT instead of THROWing on failed calls. | |
| * It also implements the awesome design pattern for initializing code as seen in Gnosis Safe Factory: https://github.com/gnosis/gnosis-safe-contracts/blob/master/contracts/ProxyFactory.sol |
Today, when a dapp calls eth_sendTransaction, the parameters are sent up to the signer, and the app is called back once, with the resulting transaction hash.
This is a great way to allow a dapp to track the progress of a signed transaction, assuming that transaction is static and not mutable.
Recent transaction backlogs have forced us at MetaMask to add a button on long-pending transanctions to "Retry with higher gas price", but if a dapp or service was tracking the signed transaction by hash, it has no way of discovering that this transaction was ever resubmitted successfully.
This is only a problem for apps that submit a transaction, and continue tracking that specific transaction hash until it is mined, but for dapps with that problem, one solution could be to add a new method, maybe called eth_sendMutableTransaction, which calls back not wit
| from web3 import Web3, HTTPProvider | |
| web3 = Web3(HTTPProvider("http://localhost:8545")) | |
| PERCENTILE = 0.6 | |
| NUMBLOCKS = 43200 | |
| # NUMBLOCKS = 1000 | |
| def getMinGasPrice(block): | |
| minPrice = None |
| // https://www.reddit.com/r/ethdev/comments/7jyzlw/50_in_ether_prize_for_puzzle_in_this_tweet/ | |
| // npm i bip39 ethereumjs-wallet allcombinations shuffle-array | |
| const bip39 = require("bip39"); | |
| const hdkey = require('ethereumjs-wallet/hdkey'); | |
| const allcombinations = require('allcombinations'); | |
| const shuffle = require('shuffle-array'); | |
| let words = 'bright summer public tenant avocado chef depend romance school reason help start'; | |
| Here are some pointers to implementing the ULC mode. Just take a look at the relevant code, then feel free to ping me whenever you have questions (I guess it will happen a few times, I tried to document the most important parts but some of the code is still a bit messy, which I apologize for in advance). | |
| - adding the ultra light client option: | |
| Add an extra option for light client mode where the user can specify a text/json ULC config file that contains a list of trusted server enodes and N out of M parameters (which may depend on how many servers we are connected to, there may be 5 servers listed but we can still accept 2 out of 3 connected). | |
| Geth parameters are implemented like this: | |
| https://github.com/ethereum/go-ethereum/blob/master/cmd/utils/flags.go#L162 | |
| Search for LightModeFlag or LightServFlag to find out how it is wired through the code. | |
| - requesting signed headers |
| pragma solidity ^0.4.18; | |
| library BytesUtils { | |
| struct slice { | |
| uint len; | |
| uint _ptr; | |
| } | |
| function memcpy(uint dest, uint src, uint len) private pure { | |
| // Copy word-length chunks while possible |
| package com.square.moshi.example; | |
| import com.squareup.moshi.RuntimeTypeJsonAdapterFactory.RuntimeType; | |
| public class Example { | |
| static class Animal { | |
| String type; | |
| String name; |
In a nutshell: the 1.6 release will be an API breaking release. All minor future releases will be similar; they mark the dawn of breaking API changes and new features will be developed on top of those. Critical- and security issues will be backported to the previous release (i.e. we will continue to support the last two versions).
