cipher.go

package main

import (
	"fmt"
	"log"
	"math/rand"
	"runtime"
	"strconv"
	"time"
)

/*
func reversed(a string) string {
	// Get Unicode code points.
	n := 0
	rune := make([]rune, len(a))
	for _, r := range a {
		rune[n] = r
		n++
	}
	rune = rune[0:n]
	// Reverse
	for i := 0; i < n/2; i++ {
		rune[i], rune[n-1-i] = rune[n-1-i], rune[i]
	}
	// Convert back to UTF-8.
	output := string(rune)
	return output
}
*/

var message string = `012222 1114142503 0313012513 03141418192102 0113 2419182119021713 06131715070119`
var keyedAlphabet string = "BHISOECRTMGWYVALUZDNFJKPQX"

func main() {

	// Determine which characters are most common and are therefore vowels.

	/*
		counts := make([]int, 26)
		for i := 0; i < len(message); i+=2 {
			if string(message[i]) == " " {
				i -= 1
				continue
			}
			num, err := strconv.Atoi(message[i:i+2]); if err != nil {
				log.Fatal(err)
			}
			counts[num-1]++
		}
		fmt.Println(counts)
	*/

	// Since 5 and 4 appear next to each other, they are most likely O and E and this is a ROT
	// cipher. 5 appears at index 13 (zero-indexed), and O appears at index 4, so we rotate the
	// alphabet 13 - 4 = 9 times.

	/*
			unkeyedAlphabet := "ZDNFJKPQXBHISOECRTMGWYVALU"

		    for i := 0; i < len(message); i+=2 {
		        if string(message[i]) == " " {
		            i -= 1
					fmt.Print(" ")
		            continue
		        }
		        num, err := strconv.Atoi(message[i:i+2]); if err != nil {
		            log.Fatal(err)
		        }
		        fmt.Print(string(unkeyedAlphabet[num]))
		    }
	*/
	runtime.GOMAXPROCS(2)

	go permute()
	permute()
	time.Sleep(100 * time.Second)

	// Try every rotation of the alphabet
	/*
		for i := 0; i < 25; i++ {
			rotatedAlphabet := keyedAlphabet[25-i:] + keyedAlphabet[:25-i]
			// fmt.Println(rotatedAlphabet)
			for i := 0; i < len(message); i += 2 {
				if string(message[i]) == " " {
					i -= 1
					fmt.Print(" ")
					continue
				}
				num, err := strconv.Atoi(message[i : i+2])
				if err != nil {
					log.Fatal(err)
				}
				fmt.Print(string(rotatedAlphabet[num]))
			}
			fmt.Println()
		}
	*/
}

func permute() {
	for i := 0; ; i++ {
		rand.Seed(int64(time.Now().Nanosecond()))
		randValues := rand.Perm(26)
		var newAlphabet string
		for i := range randValues {
			newAlphabet += string(keyedAlphabet[randValues[i]])
		}

		// Print the alphabet using newAlphabet
		output := ""
		for i := 0; i < len(message); i += 2 {
			if string(message[i]) == " " {
				i -= 1
				output += " "
				continue
			}
			num, err := strconv.Atoi(message[i : i+2])
			if err != nil {
				log.Fatal(err)
			}
			output += string(newAlphabet[num])
		}
		//time.Sleep(40*time.Millisecond)
		fmt.Println(output)
	}
}