3.1.4.1.2 BACKUPKEY_RESTORE_GUID_WIN2K
The server MUST first check the first four bytes of the wrapped secret passed in the pDataIn parameter, to see if they match the fixed values specified in section 2.2.4. If they match, the server MUST proceed as specified in section 3.1.4.1.2.1. If not, and the first four bytes of the wrapped secret correspond to a valid dwVersion value specified in section 2.2.2, then the server SHOULD<10> proceed as specified in section 3.1.4.1.2.2. In all other cases, the server MUST stop processing and return a non-zero error code.