Crypto currencies are safe. As a example when we consider bitcoin, they use block chain technology. In block chain there is a interaction between wallet to wallet and they make a chain. Day by day block achain is become larger. If anyone wants to hack block chain they have to hack all wallet in the world. There is no one could do it.
There is a phrase like that
"Impossible is nothing. It just takes time"
Take Your Own Precaution (TYOP) and leave it to time.
why is it that hackers in japan cannot be trackdown what the used of their it system their?? so it means that some of their govt information are not safe at all or maybe they their is what you called inside job ahahaha anyways all things are impossible especially for those aim is to make someone suffer inorder for them to live will, it is between the good and the evil they will make their own way to make someone's life miserable for now block chain technology is safe and we should hope and pray that they cannot find their way do destroy it..hackers are devilmade
and experiencing a high technology now ohhh keeping my fingers crossed