mcrypt_decrypt, openssl_decrypt and 0x06065064 EVP_DecryptFinal error

Question

I have a problem with the openssl_decrypt function.

Example code:

// mcrypt
$decrypted = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $data, MCRYPT_MODE_CBC, $iv);

// OpenSSL
$decrypted = openssl_decrypt($data, 'AES-256-CBC', $key, OPENSSL_RAW_DATA, $iv);

The mcrypt_decrypt function works fine. But openssl_decrypt returns FALSE and the following error:

error:06065064:digital envelope routines:EVP_DecryptFinal_ex:bad decrypt

The key is 32 bytes long and the iv 16 bytes.

Does anyone know what's wrong?

Answer 1

The solution to the problem is OPENSSL_RAW_DATA and OPENSSL_ZERO_PADDING:

$decrypted = openssl_decrypt($data, 'AES-256-CBC', $key, OPENSSL_RAW_DATA|OPENSSL_ZERO_PADDING, $iv);