A,B,C......Z re represent the numbers from 1,2,3....26. There is an encryption technique which uses a key. Key can be any number less than 26 and greater than 0. For a message ABCD, if key is 1encrypted message becomes BCDE. Similarly, if he is 5 , and message is XYZA, the encrypted message becomes CDEF. If you get an encrypte message from a friend as'FCJN'. This was encrypted using key is = 24. The original message is _.
( please whoever is the expert please try to give the answer by typing it not by clicking photos otherwise it will be unable for me to understand your handwriting thank you).