You can do it even if you use pirated windows, though you'll get watermark with text This is not a genuine copy of Windows.
Which should not be used at all, regardless of whether it works or not.
All types of cracked windows OS are infected with malware and backdoors. That's their business model.
I wouldn't touch such a system with a stick, let alone store sensitive information (passwords, private keys, etc..) on it.
From an information security based point of view, that's one of the most dangerous things you can do.