在php中加密.Net解密

I am writing some C# encrypting that is decrypted by php. They aren't working together very well. The php client has informed me of their configuration (RSSL_KEYGEN_PKCS5_V20, 256 bit AES in CBC mode, RSSL_PAD_ANSIX923). Here is what I put together:I am writing some C# encrypting that is decrypt