Even with a free key available, Starsector’s depth makes it one of the most respected "hidden gems" in PC gaming: Taking a look at Star Sector! & Key Give Away
Starsector is a labor of love made by a small team. If you love the game, you should want them to keep developing it. Pay for the key. You will sleep better, and your computer will remain malware-free.
If you eventually buy your own key to support development, you can press in the launcher to enter your new, unique code. Why You Should Eventually Buy It