Create a weak hash for "Hello world" then solve it matrix style.

HelloWorld1

package com.erezbiox1

import java.security.MessageDigest
import java.util.*
import java.util.concurrent.ThreadLocalRandom

/**
 * Created by Erezbiox1 on 22/05/2018.
 * (C) 2018 Erez Rotem All Rights Reserved.
 */ // 33 - 126 // 16

fun main(args: Array<String>){

    println("Stupid matrix decoder 9000!")
    println("Please choose if you want to decode or encode your message: ( E or D )")
    val line = readLine()!!
    when(line.trim().toLowerCase()){
        "e" -> {
            println("Please enter your message:")
            val message = readLine()!!
            println(weakHash(message))
        }
        "d" -> {
            println("Please enter your message:")
            val message = readLine()!!
            singleBruteforce(message)
        }
        else -> println("Sorry that's not an option.")
    }

}

fun singleBruteforce(weakHash: String) : String {

    val hashedLetters = Base64.getDecoder().decode(weakHash.toByteArray()).toList().chunked(3)
    val solvedLetters = StringBuilder()

    for (hashedLetter in hashedLetters) {
        var char = getRandomChar()
        while(!char.hash().contentEquals(hashedLetter.toByteArray())){
            print(solvedLetters.toString())
            print(char)
            println()
            char = getRandomChar()
            Thread.sleep(3)
        }
        solvedLetters.append(char)
    }

    val result = solvedLetters.toString()
    println(result)
    return result

}

fun weakHash(word: String) : String {
    val byteList = mutableListOf<Byte>()
    for (letter in word.toCharArray()) {
        byteList.addAll(letter.toString().hash().toList())
    }
    return Base64.getEncoder().encodeToString(byteList.toByteArray())
}

fun String.hash(algorithm: String = "MD5") : ByteArray {
    return MessageDigest.getInstance(algorithm).digest(this.toByteArray()).sliceArray(1..3)
}

fun getRandomChar() : String {
    return getRandom(32..126).toChar().toString()
}

fun getRandom(range: IntRange) : Int {
    return ThreadLocalRandom.current().nextInt(range.start, range.last + 1)
}