Patrick Cieplak cieplak

RSA Cryptosystem in Haskell

I first started functional programming a year ago using OCaml. I was learning a lot, but stopped once my schedule started to fill up. I decided that this winter I would take another shot at functional programming with Haskell. I made an end-goal of implementing the bare-bones RSA cryptosystem in Haskell and below is some commentary on what I came up with. Any comments/suggestions regarding my code and style with respect to Haskell would be greatly appreciated!

Random Number Generation

The first problem I had to tackle was random number generation. I decided to use Haskell's System.Random to generate the number. I knew that the generator wouldn't be cryptographically secure, but certainly sufficient for educational purposes. I used the simple randomRIO (m, n) method to generate a random number in the range m to n .

-- Uses System.Random to get a random Integer between m and n inclusive
randomInteger :: Integer -&gt; Integer

	{-# OPTIONS_GHC -fno-warn-type-defaults #-}
	{-# LANGUAGE NoImplicitPrelude #-}
	{-# LANGUAGE OverloadedStrings #-}
	{-# LANGUAGE ExtendedDefaultRules #-}
	{-# LANGUAGE DataKinds #-}
	{-# LANGUAGE TypeOperators #-}
	{-# LANGUAGE OverloadedLabels #-}
	{-# LANGUAGE DeriveAnyClass #-}
	{-# LANGUAGE DeriveGeneric #-}
	{-# LANGUAGE RankNTypes #-}

	/*
	* @author zz85 / https://github.com/zz85
	*
	* Ascii generation is based on http://www.nihilogic.dk/labs/jsascii/
	* Maybe more about this later with a blog post at http://lab4games.net/zz85/blog
	*
	* 16 April 2012 - @blurspline
	*/

	THREE.AsciiEffect = function ( renderer, charSet, options ) {

	/**
	* @author qiao / https://github.com/qiao
	* @author mrdoob / http://mrdoob.com
	* @author alteredq / http://alteredqualia.com/
	* @author WestLangley / http://github.com/WestLangley
	* @author erich666 / http://erichaines.com
	*/

	// This set of controls performs orbiting, dollying (zooming), and panning.
	// Unlike TrackballControls, it maintains the "up" direction object.up (+Y by default).

	#!/usr/bin/env runhaskell
	{-# LANGUAGE OverloadedStrings #-}

	module Main where

	import Control.Concurrent (threadDelay)
	import Control.Concurrent.MVar (MVar (..), putMVar, takeMVar)
	import Control.Exception (tryJust)
	import Control.Monad (forever, guard)
	import qualified Data.ByteString.Lazy as BS

	#include <sys/socket.h>
	#include <sys/un.h>
	#include <sys/event.h>
	#include <netdb.h>
	#include <assert.h>
	#include <unistd.h>
	#include <fcntl.h>
	#include <stdio.h>
	#include <errno.h>

	/*
	* This program is free software: you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation, either version 3 of the License, or
	* (at your option) any later version.
	*/

	#include <arpa/inet.h>
	#include <linux/if_packet.h>
	#include <linux/ip.h>

	# to generate your dhparam.pem file, run in the terminal
	openssl dhparam -out /etc/nginx/ssl/dhparam.pem 2048

	import Control.Concurrent
	import Control.Concurrent.Chan
	import Control.Monad
	import System.IO

	main = do
	hSetBuffering stdout NoBuffering
	handle <- openFile "/tmp/example.log" WriteMode
	sink <- newChan
	forkIO $ fileLogger handle sink

	-- {-# LANGUAGE OverloadedStrings #-}

	import Data.Text
	import Control.Monad.Trans
	import Control.Monad.Trans.Maybe
	import Control.Monad.Trans.State
	import Control.Monad.Trans.Identity
	import Control.Monad.Identity
	import Control.Monad.Logger