/* EMAIL ENCRYPTION SCRIPT */

// This script is (c) copyright 2008 by Dan Appleman under the
// GNU General Public License (http://www.gnu.org/licenses/gpl.html)
// This script is modified from an original script by Jim Tucek
// For more information, visit www.danappleman.com 
// Leave the above comments alone!
// see encryption_instructions.txt for explanation of usage

var decryption_cache = new Array();

function decrypt_string(crypted_string,n,decryption_key,just_email_address) {
  var cache_index = "'"+crypted_string+","+just_email_address+"'";

  if(decryption_cache[cache_index])               // If this string has already been decrypted, just
    return decryption_cache[cache_index];         // return the cached version.

  if(addresses[crypted_string])                   // Is crypted_string an index into the addresses array
    var crypted_string = addresses[crypted_string];   // or an actual string of numbers?

  if(!crypted_string.length)                      // Make sure the string is actually a string
    return "Error, not a valid index.";

  if(n == 0 || decryption_key == 0) {             // If the decryption key and n are not passed to the
    var numbers = crypted_string.split(' ');      // function, assume they are stored as the first two
    n = numbers[0]; decryption_key = numbers[1];  // numbers in crypted string.
    numbers[0] = ""; numbers[1] = "";             // Remove them from the crypted string and continue
    crypted_string = numbers.join(" ").substr(2);
  }

  var decrypted_string = '';
  var crypted_characters = crypted_string.split(' ');

  for(var i in crypted_characters) {
    var current_character = crypted_characters[i];
    var decrypted_character = exponentialModulo(current_character,n,decryption_key);
    if(just_email_address && i < 7)       // Skip 'mailto:' part
      continue;
    if(just_email_address && decrypted_character == 63) // Stop at '?subject=....'
      break;
    decrypted_string += String.fromCharCode(decrypted_character);
  }
    decryption_cache[cache_index] = decrypted_string;     // Cache this string for any future calls

  return decrypted_string;
}

function decrypt_and_email(crypted_string,n,decryption_key) {
  if(!n || !decryption_key) { n = 0; decryption_key = 0; }
  if(!crypted_string) crypted_string = 0;

  var decrypted_string = decrypt_string(crypted_string,n,decryption_key,false);
  parent.location = decrypted_string;
}

function decrypt_and_echo(crypted_string,n,decryption_key) {
  if(!n || !decryption_key) { n = 0; decryption_key = 0; }
  if(!crypted_string) crypted_string = 0;

  var decrypted_string = decrypt_string(crypted_string,n,decryption_key,true);
  document.write(decrypted_string);
  return true;
}

// Finds base^exponent % y for large values of (base^exponent)
function exponentialModulo(base,exponent,y) {
  if (y % 2 == 0) {
    answer = 1;
    for(var i = 1; i <= y/2; i++) {
      temp = (base*base) % exponent;
      answer = (temp*answer) % exponent;
    }
  } else {
    answer = base;
    for(var i = 1; i <= y/2; i++) {
      temp = (base*base) % exponent;
      answer = (temp*answer) % exponent;
    }
  }
  return answer;
}