Task: Bacon cipher



C#: using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace BaconCipher {
    class Program {
        private static Dictionary<char, string> codes = new Dictionary<char, string> {
            {'a', "AAAAA" }, {'b', "AAAAB" }, {'c', "AAABA" }, {'d', "AAABB" }, {'e', "AABAA" },
            {'f', "AABAB" }, {'g', "AABBA" }, {'h', "AABBB" }, {'i', "ABAAA" }, {'j', "ABAAB" },
            {'k', "ABABA" }, {'l', "ABABB" }, {'m', "ABBAA" }, {'n', "ABBAB" }, {'o', "ABBBA" },
            {'p', "ABBBB" }, {'q', "BAAAA" }, {'r', "BAAAB" }, {'s', "BAABA" }, {'t', "BAABB" },
            {'u', "BABAA" }, {'v', "BABAB" }, {'w', "BABBA" }, {'x', "BABBB" }, {'y', "BBAAA" },
            {'z', "BBAAB" }, {' ', "BBBAA" }, 
        };

        private static string Encode(string plainText, string message) {
            string pt = plainText.ToLower();
            StringBuilder sb = new StringBuilder();
            foreach (char c in pt) {
                if ('a' <= c && c <= 'z') sb.Append(codes[c]);
                else sb.Append(codes[' ']);
            }
            string et = sb.ToString();
            string mg = message.ToLower();  
            sb.Length = 0;
            int count = 0;
            foreach (char c in mg) {
                if ('a' <= c && c <= 'z') {
                    if (et[count] == 'A') sb.Append(c);
                    else sb.Append((char)(c - 32)); 
                    count++;
                    if (count == et.Length) break;
                }
                else sb.Append(c);
            }

            return sb.ToString();
        }

        private static string Decode(string message) {
            StringBuilder sb = new StringBuilder();
            foreach (char c in message) {
                if ('a' <= c && c <= 'z') sb.Append('A');
                else if ('A' <= c && c <= 'Z') sb.Append('B');
            }
            string et = sb.ToString();
            sb.Length = 0;
            for (int i = 0; i < et.Length; i += 5) {
                string quintet = et.Substring(i, 5);
                char key = codes.Where(a => a.Value == quintet).First().Key;
                sb.Append(key);
            }
            return sb.ToString();
        }

        static void Main(string[] args) {
            string plainText = "the quick brown fox jumps over the lazy dog";
            string message = "bacon's cipher is a method of steganography created by francis bacon. " +
                "this task is to implement a program for encryption and decryption of " +
                "plaintext using the simple alphabet of the baconian cipher or some " +
                "other kind of representation of this alphabet (make anything signify anything). " +
                "the baconian alphabet may optionally be extended to encode all lower " +
                "case characters individually and/or adding a few punctuation characters " +
                "such as the space.";
            string cipherText = Encode(plainText, message);
            Console.WriteLine("Cipher text ->\n{0}", cipherText);
            string decodedText = Decode(cipherText);
            Console.WriteLine("\nHidden text ->\n{0}", decodedText);
        }
    }
}


Go: package main

import(
    "fmt"
    "strings"
)

var codes = map[rune]string {
    'a' : "AAAAA", 'b' : "AAAAB", 'c' : "AAABA", 'd' : "AAABB", 'e' : "AABAA",
    'f' : "AABAB", 'g' : "AABBA", 'h' : "AABBB", 'i' : "ABAAA", 'j' : "ABAAB",
    'k' : "ABABA", 'l' : "ABABB", 'm' : "ABBAA", 'n' : "ABBAB", 'o' : "ABBBA",
    'p' : "ABBBB", 'q' : "BAAAA", 'r' : "BAAAB", 's' : "BAABA", 't' : "BAABB",
    'u' : "BABAA", 'v' : "BABAB", 'w' : "BABBA", 'x' : "BABBB", 'y' : "BBAAA",
    'z' : "BBAAB", ' ' : "BBBAA",  
}

func baconEncode(plainText string, message string) string {
    pt := strings.ToLower(plainText)
    var sb []byte
    for _, c := range pt {
        if c >= 'a' && c <= 'z' {
            sb = append(sb, codes[c]...)
        } else {
            sb = append(sb, codes[' ']...)
        }
    }
    et := string(sb)
    mg := strings.ToLower(message)  
    sb = nil  
    var count = 0
    for _, c := range mg {
        if c >= 'a' && c <= 'z' {
            if et[count] == 'A' {
                sb = append(sb, byte(c))
            } else {
                sb = append(sb, byte(c - 32))  
            }
            count++
            if count == len(et) { break }
        } else {
            sb = append(sb, byte(c))
        }
    }
    return string(sb)
}

func baconDecode(message string) string {
    var sb []byte
    for _, c := range message {
        if c >= 'a' && c <= 'z' {
            sb = append(sb, 'A')
        } else if c >= 'A' && c <= 'Z' {
            sb = append(sb, 'B')
        }
    }
    et := string(sb)
    sb = nil  
    for i := 0; i < len(et); i += 5 {
        quintet := et[i : i + 5]
        for k, v := range codes {
            if v == quintet {
                sb = append(sb, byte(k))
                break
            }
        }
    }
    return string(sb)
} 

func main() {
    plainText := "the quick brown fox jumps over the lazy dog"
    message := "bacon's cipher is a method of steganography created by francis bacon." +
        "this task is to implement a program for encryption and decryption of " +
        "plaintext using the simple alphabet of the baconian cipher or some " +
        "other kind of representation of this alphabet (make anything signify anything). " +
        "the baconian alphabet may optionally be extended to encode all lower " +
        "case characters individually and/or adding a few punctuation characters " +
        "such as the space."
    cipherText := baconEncode(plainText, message)
    fmt.Printf("Cipher text ->\n\n%s\n", cipherText)
    decodedText := baconDecode(cipherText)
    fmt.Printf("\nHidden text ->\n\n%s\n", decodedText)
}