[sorbits]

As someone else said, you do not store coins anywhere, they are derived from the public ledger (block chain).

What you store is your private key.

Your private key was generated together with your public key, and your public key is, well, public.

So the question is, can someone re-generate your private key?

In theory, yes, it is possible. In practice, it takes a very very long time.

But sometimes flaws are found in the generation process, like a weak pseudo-random number generated used, which significantly reduces the solution space, and then it becomes feasible.