Decrypts the XML data
Use this method to perform data decryption. This method returns an error code (0 on success). Before calling this method, load the encrypted data using Load method. After successful decryption you can access decrypted data using DecryptedData and optionally using DecryptedNode and DecryptedNodeList (if the encrypted data was an XML node or node list respectively).
Before calling Decrypt you should specify the key to be used for decryption (set KeyData property). If the encryption key was also encrypted, you need to specify pre-shared secret, needed for key decryption, via KeyEncryptionKeyData property.