I think about the only way to be 100% secure anymore....any where....is to not exist.
That pretty well sums it up.
I have bought things online as much as anyone,have an online brokerage account,use Ebay and Paypal,pay all my credit cards online as well as most bills.
The one time in my life there was a security issue it was with an individual at a grocery chain that stole some card receipts.
Crap can happen,just depends on how much one wants to restrict their lives and/or activities.
Each to their own comfort level.