CryptoWorkbench/columntransposition.csharp

using System;
using System.IO;
using System.Text;
using System.Collections.Generic;

namespace AniNIX.Crypto {
    public class ColumnTransposition : Cipher {

        public override String Description() { return "Column Transposition cipher suite\nFormat is col <command> key1 [key2...]\nThe key format is any word to use for the transposition.\nThis cipher will use an irregular columnar transposition, without padding the input string.\n"; } 
         public override String Command() { return "col"; }
         public ColumnTransposition(Workbench w) : base (w) {}
         public ColumnTransposition() {}

         /// <summary> 
         /// Get the order of columns from a key
         /// </summary>
         /// <returns>an array of ints indicating order</returns>
        private int[] GetColumnOrder(String key) {
            // Create an ordered list and sort from the key.
            List<char> orderList = new List<char>();
            for (int i = 0; i < key.Length; i++) {
                orderList.Add(key[i]);
            }
            orderList.Sort();
            char[] charArr = orderList.ToArray();
            int[] returnOrderIndexes = new int[key.Length];
            Console.Write("Found key order: ");
            // for each character in the key, find the index in tke sorted array
            for (int i = 0; i < key.Length; i++) {
                for (int j = 0; j < charArr.Length; j++) {
                    if (key[i] == charArr[j]) {
                        Console.Write(String.Format("{0} ",j+1));
                        returnOrderIndexes[j] = i;
                        break;
                    }
                }
            }
            Console.WriteLine("");
            return returnOrderIndexes;
        }

        /// <summary>
        /// Encrypt a string with the cipher. See https://en.wikipedia.org/wiki/Transposition_cipher#Columnar_transposition for an example of how this works.
        /// </summary>
        /// <param name="workSpace">The working copy of the cipher</param>
        /// <param name="inputText">The original cipher</param>
        /// <param name="line">The user input</param>
        /// <returns>The encrypted string</returns>
        public override String Encrypt(String workSpace, String cipher, String[] line) {
            if (line.Length < 3) {
                Console.Error.WriteLine("Bad formatting.");
                return workSpace;
            }
            //Remove newlines.
            String workSpaceNoNewline = workSpace.Replace("\n","");
            char[] changed = workSpaceNoNewline.ToCharArray();
            // Create a grid from the key.
            CharGrid cg = new CharGrid(workSpaceNoNewline,line[2].Length,false);
            char[][] encryptionGrid = cg.ToArray();
            //Get the key order. 
            int[] keyOrder = GetColumnOrder(line[2]);
            Console.Write(cg.ToString());
            int k = 0;
            // Replace each character by the character in the right place in the character grid.
            for (int j = 0; j < encryptionGrid[0].Length; j++) {
                for (int i = 0; i < encryptionGrid.Length; i++) {
                    if (i != (encryptionGrid.Length-1) || keyOrder[j] < encryptionGrid[i].Length) {
                        changed[k] = encryptionGrid[i][keyOrder[j]];
                        k++;
                    }
                }
            }
            String toReturn = new String(changed);
            //Re-insert newlines.
            for (k = 0; k < workSpace.Length; k++) {
                if (workSpace[k] == '\n') {
                    toReturn = toReturn.Insert(k,"\n");
                }
            }
            return toReturn;
        }

       /// <summary>
       /// Decrypt a string with the cipher
       /// </summary>
       /// <param name="workSpace">The working copy of the cipher</param>
       /// <param name="inputText">The original cipher</param>
       /// <param name="line">The user input</param>
       /// <returns>The decrypted string</returns> 
        public  override String Decrypt(String workSpace, String cipher, String[] line) {
            if (line.Length < 3) {
                Console.Error.WriteLine("Bad formatting.");
                return workSpace;
            }
            // Remove newlines.
            String workSpaceNoNewline = workSpace.Replace("\n","");
            // Find the key order.
            int[] keyOrder = GetColumnOrder(line[2]);
            // Create a new chargrid to solve from.
            CharGrid cg = new CharGrid(workSpaceNoNewline,line[2].Length,keyOrder);
            Console.Write(cg.ToString());
            char[][] cgArray = cg.ToArray();
            StringBuilder sb = new StringBuilder();
            // For each row, read the row and add to the solution.
            for (int i=0; i < cgArray.Length; i++) {
                sb.Append(new String(cgArray[i]));
            }
            String toReturn = sb.ToString();
            // Add back in the newlines.
            for (int i=0; i < workSpace.Length; i++) {
                if (workSpace[i] == '\n') {
                    toReturn = toReturn.Insert(i,"\n");
                }
            }
            return toReturn;
        }
    }
}