Naught about a form of digital protection? (4)
I believe the answer is:
nail
'form of digital protection?' is the definition.
'naught about a' is the wordplay.
'naught' becomes 'nil' (synonyms).
'about' indicates putting letters inside.
'nil' placed around 'a' is 'NAIL'.
(Other definitions for nail that I've seen before include "Fixer (on finger?)" , "Secure" , "Fixing pin" , "Small metal spike" , "Growth on digit" .)