What would, if any, be the name of the phobia of a person who lives in constant fear of others breaking into their accounts / misusing their personal information? I've found some slightly related phobias such as "nomophobia", but none of them are quite what I'm looking for.
As kindly suggested by Ermanen and John Lawler, the lack of a particular word might prompt you to coin your own -phobia in this case. Most names for a fear simply comprise the subject of the fear in Greek with phobia(greek for fear) as a suffix.
This site mentions a whole lot of them. The rule about the first word being greek doesn't seem to be a very hard rule there. With it being replaced by a latin word
Albuminurophobiafor example take the latin words for respectively Spain (don't really know why you'd be afraid of that) and a kidney protein. To indicated fear of Spain, and fear of kidney diseases.
So I guess as long as you pick a word that sounds slighty fancy. You match the phobia criteria I reckon. My suggestions would be:
identitatokleptophobiawhich is using Latin, but hey who cares:) I wouldn't know if there's a Greek word for identity.
kleptotechnophobiafear of theft by electronic means
technokleptophobiafear of theft of electronic possessions
As John Lawler has pointed out, techno as a prefix might be a bit broad. However, if you're very strictly sticking to the Greek meaning of the word. Electro actually means amber (the material). Of which our word for electricity might be derived. Which would suggest
electrokleptophobia means you're afraid someone is intent on stealing your precious amber:).
Also of course the meaning of these words might be a bit ambiguous. However, this seems to be true for a lot of the words in the list I mentioned before.