Decrypt AES-CBC in php from as3crypto

Question

I've found a lot of discussions on this but none seem to get this working for me so any help is appreciated. I'm encoding some text in flash using the as3crypto library and then sending that encrypted text to a php script where I need to decode it. The encryption and decryption works just fine inside of flash but I'm unable to get it to decrypt in php.

Here is the code I have in Flash

private static const KEY:String = "AxiKzCRH5arSABesX9bH2lTSxYmAGEEz";

private static function encrypt(input:String, key:String, algorithm:String = "aes-cbc", padding:String = "None"):String {
    var kdata:ByteArray = Base64.decodeToByteArray(key);
    var data:ByteArray = Hex.toArray(Hex.fromString(input));
    var pad:IPad = padding == "pkcs5" ? new PKCS5 : new NullPad;
    var mode:ICipher = Crypto.getCipher("simple-" + algorithm, kdata, pad);
    pad.setBlockSize(mode.getBlockSize());
    mode.encrypt(data);

    return Hex.fromArray(data);
}

var text-to-send-to-php:String = encrypt('test text', KEY);

And here is the code I have so far in php that isn't working

<?php
$key = 'AxiKzCRH5arSABesX9bH2lTSxYmAGEEz';
$encrypted_text = the-text-i-get-from-flash;

$td = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');

$iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_DEV_URANDOM);
mcrypt_generic_init($td, $key, $iv);

$s = mdecrypt_generic($td, $encrypted_text);
echo 'decrypted = ' . $s;

mcrypt_generic_deinit($td);
mcrypt_module_close($td);
?>

Answer 1

So I figured it was an issue with encoding/decoding, but it was also an issue with the IV. Here is the final working code in php

<?php
$key = base64_decode('AxiKzCRH5arSABesX9bH2lTSxYmAGEEz');
$encrypted_text = the-text-i-get-from-flash;
$encrypted_text = hex2bin($encrypted_text);

$td = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
$blocksize = mcrypt_enc_get_block_size($td);

$iv = substr($encrypted_text, 0, $blocksize);
$encrypted_text = substr($encrypted_text, $blocksize);

mcrypt_generic_init($td, $key, $iv);

$username = mdecrypt_generic($td, $encrypted_text);

mcrypt_generic_deinit($td);
mcrypt_module_close($td);
?>