Scramble binary files to make it unusable with restore option

filescrambler.go

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"math/rand"
	"os"
)

const (
	fileIn   = "inoriginal.exe"
	fileOut  = "scrambled.exe"
	fileOut2 = "insrestored.exe"
	seed     = 1234567890
)

func seedFunc(len int) []int {
	rand.Seed(seed)
	arr := make([]int, len)
	for idx := 0; idx < len; idx++ {
		arr[idx] = rand.Intn(idx + 1)
	}
	return arr
}

func unscramble(slice []byte) []byte {
	n := len(slice)
	s := seedFunc(n)
	for i := 1; i < n; i++ {
		j := s[n-i-1]
		slice[i], slice[j] = slice[j], slice[i]
	}
	return slice
}

func scramble(slice []byte) []byte {
	n := len(slice)
	s := seedFunc(n)
	for i := n - 1; i > 0; i-- {
		j := s[n-i-1]
		slice[i], slice[j] = slice[j], slice[i]
	}
	return slice
}

func main() {

	fStatus, err := os.Stat(fileIn)
	if err != nil {
		log.Fatal(err)
	}

	bytesIn, err := ioutil.ReadFile(fileIn)
	if err != nil {
		fmt.Println(err)
		return
	}

	bytesOut := scramble(bytesIn)
	ioutil.WriteFile(fileOut, bytesOut, fStatus.Mode())

	bytesOut2 := unscramble(bytesOut)
	ioutil.WriteFile(fileOut2, bytesOut2, fStatus.Mode())

	fmt.Println("finished.")
}