How to resolve bug RC4 encrypt-decrypt on iPAD with AIR15 only

Question

Hi everybody,
I have some trouble with AIR15 only, In the past, I created a small game on iPad It could send or receive messge from server. I used lib as3crypto.swc encrypt or decrypt message (RC4). But when I upgrade to AIR15 encrypt-decrypt cannot work ( Another thing about this crash is that it only happens with a release (adhoc or appstore) build but NOT with a debug build). I check so many time but i don't know what is problem here.
Please help me, thanks so much any advice.
P/S: My game have many swf files (code and resource). I must combine multiple SWF files into one.
Class RC4.as
import com.hurlant.crypto.prng.ARC4;
import com.hurlant.util.Base64;
import com.hurlant.util.Hex;
import flash.utils.ByteArray;
public class RC4
  private static const key:String = "keytest";
  private static var byteKeys:ByteArray = Hex.toArray(Hex.fromString(key));
  private static var rc4:ARC4 = new ARC4();
  public static function encrypt(clearText:String):String
  var byteText:ByteArray = Hex.toArray(Hex.fromString(clearText));
  rc4.init(byteKeys);
  rc4.encrypt(byteText);
  return Base64.encodeByteArray(byteText);
public static function decrypt(encryptedText:String):String
  var byteText:ByteArray = Base64.decodeToByteArray(encryptedText);
  rc4.init(byteKeys);
  rc4.decrypt(byteText);
  return Hex.toString(Hex.fromArray(byteText));

Answer 1

Sorry, exact message is "this movie could not be played".
There are hundreds of posts about this message but no one states a clear solution to the problem.
Your help will be much appreciated.
Thank you.