Brute Force Search Algorithm

Making a brute force search algorithm. A user enters a sequence of upper case letters into the text box and the script will find the password through the brute force method. My problem is that it works with strings of 1 or 2 letters, but goes into an infinite loop when I do anymore than 2 letters and I can't figure out why. Sorry for the messy code.

 public Text text1;
     public Text text2;
     public InputField input;
     public Button button;
 
     private int tempIndex = 25;
     private string[] charList;
     private int numDigits = 1;
     private List<string> curGuess = new List<string>();
     private int numGuesses = 0;
     private string actGuess;
     private string password;
     private int indexNum = 0;
     private float tempfloat = 0.0f;
 
     // Use this for initialization
     void Start () {
         charList = new string[] {"","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
     }
 
     public void bruteForce() {
         password = input.text;
         numGuesses = 0;
         indexNum = 0;
         tempIndex = 26;
         numDigits = 1;
         actGuess = "";
         curGuess = new List<string> ();
         curGuess.Add ("");
         while (actGuess != password) {
             indexNum += 1;
             curGuess [numDigits - 1] = charList [((indexNum + 26) % 26)];
             numGuesses += 1;
 
             actGuess = string.Join ("", curGuess.ToArray());
 
             if (actGuess != password) {
                 if (((indexNum + 26) % 26) == 0) {
                     if (indexNum == tempIndex) {
                         tempIndex = 26 ^ (numDigits + 1);
                         numDigits += 1;
                         curGuess.Add ("");
                     }
                     for (int i = 1; i <= curGuess.Count - 1; i++) {
                         tempfloat = Mathf.Floor(indexNum / (26 ^ i));
                         tempfloat += 26;
                         tempfloat = tempfloat % 26;
                         curGuess [numDigits - i - 1] = charList [(int)tempfloat];
                     }
                 }    
             }
         }
         Debug.Log (actGuess);
         text1.text = "Password is " + actGuess;
         text2.text = "Num Guesses " + numGuesses;
 
     }