Yes, that software exists. The people who did this to you have the software and will use it for you if you pay them. The problem is that if it is encrypted then you need the encryption key that was used and you can bet dollars to donuts that you won't find that key anywhere on your computer. If we don't have the key, we can't do anything either.
This is why you have firewalls and anti-virus packages and total network security packages. And backups.