Straight out of what's revolutionary in data encryption (4)
I believe the answer is:
neat
'straight' is the definition.
('neat' can be a synonym of 'straight')
'what's revolutionary in data encryption' is the wordplay.
'what's revolutionary' says the letters should be written backwards.
'in' indicates a hidden word.
'taen' can be found hidden inside 'data encryption'.
'taen' written backwards gives 'NEAT'.
'out of' is the link.
(Other definitions for neat that I've seen before include "beef" , "Pure" , "As whisky may be" , "(Of alcohol) not diluted" , "Bovine animal" .)