Help, AES256CBC is adding 16bytes at the start of decrypted text

[tonimarin]

Hi,
first of all, thank you for this excellent library I use it in different projects.
I am now stuck trying to encrypt with AES256CBC: when my counterpart decrypts data I send they can decrypt data, but there appear 16 bytes at the start of the decritpted string, so their XML reader blows.

The code I am using is just this:

$fileEncryptor = new XMLSecurityKey(XMLSecurityKey::AES256_CBC);        
$session_key = $fileEncryptor->generateSessionKey();
$encryptedData = $fileEncryptor->encryptData($data);

Then I send them the session key and the IV (encrypted with their PK). It works fine, but of those 16 bytes...

Thanks in advance!

Antoni Marin

[tonimarin]

Oh sorry, noob mistake, my counterpart was not aware that IV was prepended to the encrypted data.