Each program's dated cipher keyed in (1,3)
I believe the answer is:
a pop
'each' is the definition.
(eg 'one pound a pop' can mean 'one pound each')
'program's dated cipher keyed in' is the wordplay.
I cannot really see how this works, but
'cipher' could be 'o' (old-fashioned term for zero) and 'o' is located in the answer.
'program' could be 'app' (type of computer program) and 'app' is located in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for a pop that I've seen before include "What an orphan might wish for" , "individually" .)