PHP openSSL and Padding

I have been having difficulties encrypting in PHP and then properly decrypting it in C#. I believe I have gotten to the heart of the issue - some reason the data being encrypted by openssl_encrypt does not seem to add the proper padding.

I keep getting an error message in Visual Studio that the input was not a full block. I tried placing some breakpoints and discovered that the size of the cipher text is indeed wrong (I think) - 24 bytes. Both the IV and Key length are correct (16 and 32 respectively), but the input is not (based on the block size, it should have been padded to 32 bytes - right?). I was under the impression that openSSL used PKCS7 padding by default, but that does not seem to be the case.

What am I doing wrong, is PHP not doing the padding correctly, or am I somehow stripping it when I write it to text file and copy and paste? Oddly enough, I can decrypt it just fine in PHP using the following:

openssl_decrypt(hex2bin("6a7a36662f337042666e3159374331504269486e56413d3d"), "aes-256-cbc", hex2bin("myKey"), 0, hex2bin("3a6f13459776c43f81737d72fea03b67"));

Here is the PHP:

try {


// DO ONLY ONCE //
/* $handler = fopen("../../etc/insurance.txt", "w");
fwrite($handler, bin2hex(openssl_random_pseudo_bytes(32))); // convert to hex
fclose($handler); 
*/

$passFile = '../../etc/insurance.txt';
$handler = fopen($passFile, 'r');
$key = fread($handler, filesize($passFile));
$key = hex2bin($key); // openssl_encrypt expects binary, convert back


fclose($handler);

} catch (Exception $e) {
echo $e->getMessage();
}

part of the class used for encryption:

class dataHandler {


private $keyString;
private $employee;

function __construct($key, $employeeID) {
$this->keyString = $key; // encrypt sensitve data
$this->employee = $employeeID; // random id for identification
}

private function encrypt($data) {
$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length(METHOD));
$encrypted = openssl_encrypt($data, METHOD, $this->keyString, 0, $iv);

// both encrypted and $iv are binary, convert to hex for writing
$encrypted = bin2hex($encrypted );
$iv = bin2hex($iv);

$encrypted .= ":" . $iv; // append iv for access later

retu $encrypted;

}

public function insertEmployee($ssn, $lastName, $firstName, $gender, $email, $address, $location, $birth, $decision, $dependents, $vision) {

 if(!$vision ) {
 $vision = 'declined';
 } 

 $employeeData = "id,ssn,last,first,gender,email,address,location,birth,decision,dependents,vision" . PHP_EOL;
 $employeeData .= "$this->employee, $ssn, $lastName, $firstName, $gender, $email, $address, $location, $birth, $decision, $dependents, $vision";

retu $employeeData;

}

and an example of how it might be used

$dh = new dataHandler($key, $employeeID);

$employeeData = $dh->insertEmployee($ssn, $lastName, $firstName, $gender, $email, $address, $location, $birth, $selectedPlan, $eligibleDependents, $vision);

I think the issue is in the PHP rather than the C#, but I will include the latter just in case:

namespace Decryption
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private byte[] hexToBin(String hexString) {
            int charCount = hexString.Length;
            byte[] output = new byte[charCount / 2];
            for(int i = 0; i < charCount; i += 2) {
                output[i / 2] = Convert.ToByte(hexString.Substring(i, 2), 16);
            } 


            retu output;
        }

        private  void decrypter (byte[] cipherText, byte[] key, byte[] iv) {
            String outputString;
            try
            {
                using (Aes myAes = Aes.Create())
                {
                    myAes.KeySize = 256;
                    myAes.Mode = CipherMode.CBC;
                    myAes.Key = key;
                    myAes.IV = iv;
                    myAes.Padding = PaddingMode.



                    ICryptoTransform myDecrypter = myAes.CreateDecryptor(myAes.Key, myAes.IV);

                    using (MemoryStream memory = new MemoryStream(cipherText))
                    {
                        using (CryptoStream cryptStream = new CryptoStream(memory, myDecrypter, CryptoStreamMode.Read))
                        {
                            using (StreamReader reader = new StreamReader(cryptStream))
                            {
                               outputString = reader.ReadToEnd();

                            }
                        }
                    }

                }
                System.IO.File.WriteAllText("test.txt", outputString);

            }
            catch (Exception e)
            {
                Console.Write(e.Message);
            }
    }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {

            byte[] cipher = this.hexToBin("51436c6777374c576d423570487941626850736969513d3d");

            byte[] iv = this.hexToBin("6fea9ed1032cf452f7fe72b2af698721");
            byte[] key = this.hexToBin("47062ee9fba8eff4b83626e67b26ef1ffc506936a980f8c71641202c51698716");

            this.decrypter(cipher, key, iv);
        }
    }
}

I have been struggling with this for some time now, so I would really appreciate any help.

Thanks!