It seems to me there is much fear whether Bitcoin is legal or not in many places around the world. It isnunderstandable as most countries do not yet have systemic legislation on crypto assets, going as far as not even being able to legally define crypto currencies.
The answer to the question if Bitcoin is legal in such circumstances will depend on where one is from and the legal principles enshrined in their legal systems. In English common law system there is a principle that everything that is not expressly forbidden, is allowed. Try to find out if this is a principle where you are from. It has been adopted in many other countries as well.
Your starting point can be your consistution. If there is a general principle of freedom enacted in your constitution, it is a good start.
The next important principle in many legal systems is that there can be no crime nor criminal reprecusions if there was no previous law prohibiting certain acts as criminal (precisely), in latin: Nullum crimen, nulla poena sine praevia lege poenali, also: lege certa. This principle should be widely accepted around the world. Again, check your constitution. This principle guarantees that at the very least one will not be criminally persecuted for acquiring, holding or selling crypto assets if there was no law criminalising these actions at the time when they were executed.
I hope this will help the beginning of one's search if they are troubled by these questions.
Well, technically, you'd have to have some sort of legislation that is put in place before bitcoin can be considered to be outlawed.
However, a country can be very negative towards the adoption of bitcoin, and show signs that they are actively trying to restrict people's access to bitcoin, without necessarily having to have the legislation to back it up. For example, banning banks from dealing with crypto businesses and transactions by the RBI, which is not technically law.
In that case, you never know when exactly restrictions are going to come down so you may want to be more careful when dealing with crypto services. But generally, you shouldn't be worried about an unregulated bitcoin market which is still the case in many countries at the moment, if there is no specific laws stating otherwise. And even if there was, I doubt that ownership would be illegal, it would be a trading ban at maximum in most cases.