Manipulate PIN for digital protection (10)
I believe the answer is:
fingernail
'digital protection' is the definition.
(digit can mean a finger)
'manipulate pin' is the wordplay.
'manipulate' becomes 'finger' (finger can mean to manipulate or fiddle with).
'pin' becomes 'nail' (I've seen this before).
'finger'+'nail'='FINGERNAIL'
'for' acts as a link.
(Other definitions for fingernail that I've seen before include "One in ten" , "Part of hand" , "extreme protection results" .)