vietlq

Threshold Signatures

This text is a procedure for t-of-k threshold signatures.

The symbols and functions used are defined in the following URL.

https://github.com/sipa/bips/blob/bip-schnorr/bip-schnorr.mediawiki

Introduction

vietlq

module Peano = struct
  type z = Zero
  type 'a s = Succ

  type 'a t =
    | Z : z t
    | S : 'a t -> 'a s t
  and zero = z t

  let zero : z t = Z

vietlq

# Raw transaction API example work-through
# Send coins to a 2-of-3 multisig, then spend them.
#
# For this example, I'm using these three keypairs (public/private)
# 0491bba2510912a5bd37da1fb5b1673010e43d2c6d812c514e91bfa9f2eb129e1c183329db55bd868e209aac2fbc02cb33d98fe74bf23f0c235d6126b1d8334f86 / 5JaTXbAUmfPYZFRwrYaALK48fN6sFJp4rHqq2QSXs8ucfpE4yQU
# 04865c40293a680cb9c020e7b1e106d8c1916d3cef99aa431a56d253e69256dac09ef122b1a986818a7cb624532f062c1d1f8722084861c5c3291ccffef4ec6874 / 5Jb7fCeh1Wtm4yBBg3q3XbT6B525i17kVhy3vMC9AqfR6FH2qGk
# 048d2455d2403e08708fc1f556002f1b6cd83f992d085097f9974ab08a28838f07896fbab08f39495e15fa6fad6edbfb1e754e35fa1c7844c41f322a1863d46213 / 5JFjmGo5Fww9p8gvx48qBYDJNAzR9pmH5S389axMtDyPT8ddqmw

# First: combine the three keys into a multisig address:
./bitcoind createmultisig 2 '["0491bba2510912a5bd37da1fb5b1673010e43d2c6d812c514e91bfa9f2eb129e1c183329db55bd868e209aac2fbc02cb33d98fe74bf23f0c235d6126b1d8334f86","04865c40293a680cb9c020e7b1e106d8c1916d3cef99aa431a56d253e69256dac09ef122b1a9

vietlq

Using Git

Global Settings

• Related Setup: https://gist.github.com/hofmannsven/6814278
• Related Pro Tips: https://ochronus.com/git-tips-from-the-trenches/
• Interactive Beginners Tutorial: http://try.github.io/
• Git Cheatsheet by GitHub: https://services.github.com/on-demand/downloads/github-git-cheat-sheet/

vietlq

Monadic operations in C++

This began as a further attempt to implement the Maybe monad in C++, but quickly spiralled out of control and now includes an implementation of the List monad as well (using std::list!). This is really for my own amusement rather than to try and do anything useful with them. It also gave me an excuse to try out C++ 11 lambda functions for the first time.

My original implementation defined a macro called MBind which caused a number of problems -- thankfully [PJayB][pjayb] managed to find a way around that so

vietlq

module MaybeMonad = struct
	type 'a t = None | Maybe of 'a

	let return (a: 'a) : 'a t = Maybe a

	let (>>=) (m: 'a t) (f: 'a -> 'b t) : 'b t = match m with
		| None -> None
		| Maybe a -> f a

	let get (m: 'a t) (a: 'a) = match m with

vietlq

type z
type 'a s

(* Sadly enough, without kind restrictions, this still allows nonsense types like *)
type nonsense = int s
(* GHC 7.6 supports this (lifting types to kinds & kind constraints) ;-) *)

type (_, _) llist =
  | Nil : (z, 'a) llist
  | Cons : ('a * ('l, 'a) llist) -> ('l s, 'a) llist

vietlq

/**
 * Base contract that all upgradeable contracts should use.
 * 
 * Contracts implementing this interface are all called using delegatecall from
 * a dispatcher. As a result, the _sizes and _dest variables are shared with the
 * dispatcher contract, which allows the called contract to update these at will.
 * 
 * _sizes is a map of function signatures to return value sizes. Due to EVM
 * limitations, these need to be populated by the target contract, so the
 * dispatcher knows how many bytes of data to return from called functions.

vietlq

/***
* 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

vietlq

// 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 Jordi Baylina for this way of deploying contracts https://gist.github.com/jbaylina/e8ac19b8e7478fd10cf0363ad1a5a4b3

// Forwarder is slightly modified to only return 256 bytes (8 normal returns)

// Deployed Factory in Kovan: https://kovan.etherscan.io/address/0xaebc118657099e2110c90494f48b3d21329b23eb

// Example of a Forwarder deploy using the Factory: https://kovan.etherscan.io/tx/0xe995dd023c8336685cb819313d933ae8938009f9c8c0e1af6c57b8be06986957
// Just 66349 gas per contract