Text Obfuscation

textmanager.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace ancientcode {
  public class TextManager { 
      private TextManagerHelper hlp = new TextManagerHelper();
      private Random rnd = new Random(); 

      public String convert(String text) {
          string result = "";
          var pts = hlp.convert(text).ToList();

          for (int i = 0; i < pts.Count; i++) {
              if (pts[i].Type == TextPartType.WORD
                  && rnd.NextDouble() < 0.2) {
                  if (i + 2 < pts.Count) {
                      var t = pts[i];
                      pts[i] = pts[i + 2];
                      pts[i+2] = t;
                  }
              }
          } 

          for (int i1 = 0; i1 < pts.Count; i1++) {
              if (rnd.NextDouble() < 0.2) {
                  pts.Insert(i1, new TextPart(" ", TextPartType.NONWORD));
                  i1++;
                  String[] wds = { "and", "so", "however", "maybe" };
                  int ind = rnd.Next(wds.Length);
                  pts.Insert(i1, new TextPart(wds[ind], TextPartType.WORD));
                  i1++;
                  pts.Insert(i1, new TextPart(" ", TextPartType.NONWORD));
              }
          } 

          String result2 = ""; 

          foreach (var prt in pts) {
              result2 += prt.Contents;
          } 

          result = result2;
          result = Regex.Replace(result, "[\\?!-\\.,:;'\\(\\)]", "");

          var result1 = ""; 

          for (int i2 = 0; i2 < result.Split(' ').Length - 1; i2++) {
          if (rnd.NextDouble() < 0.5) {
                  char[] chrs = { '.', ',', '!' };
                  var j = rnd.Next(chrs.Length);
                  result1 += result.Split(' ')[i2] + chrs[j];
              } else {
                  result1 += result.Split(' ')[i2] + " ";
              }
          }
          result1 += result.Split(' ')[result.Split(' ').Length - 1];
          result = result1; 

          String result3 = "";
          char[] textArray = result.ToCharArray(); 

          foreach (var ch in textArray) {
              if (rnd.NextDouble() < 0.3) {
                  char nch;
                  if (char.IsLower(ch)) {
                      nch = char.ToUpper(ch);
                  } else {
                      nch = char.ToLower(ch);
                  } 

                  result3 += nch;
              } else {
                  result3 += ch;
              }
          }

          result = result3.Replace(" ", "");

          return result;
      } 
   }
}

textmanagerhelper.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace ancientcode {
    class TextManagerHelper {
      public IEnumerable<TextPart> convert(string text) {
          var contents = "";
          var type = TextPartType.WORD;
          for (var i = 0; i < text.Length; i++) {
              if (char.IsLetter(text[i])) {
                  if (type == TextPartType.WORD) {
                      contents += text[i];
                  }
                  else {
                      if (contents != "") yield return new TextPart(contents, type);
                      contents = text[i].ToString();
                      type = TextPartType.WORD;
                  }
              }
              else {
                  if (type == TextPartType.NONWORD) {
                      contents += text[i];
                  }
                  else {
                      if (contents != "") yield return new TextPart(contents, type);
                      contents = text[i].ToString();
                      type = TextPartType.NONWORD;
                  }
              }
          }
          yield return new TextPart(contents, type);
      }
    }
}

textpart.cs

namespace ancientcode {
    enum TextPartType { WORD, NONWORD }

    class TextPart {
        public TextPart(string content, TextPartType type) {
            Contents = content;
            Type = type;
        }

        public string Contents { get; }
        public TextPartType Type { get; }
    }
}

Source: https://www.infoq.com/articles/natural-course-refactoring/