In the movie “The Imitation Game,” there is a scene that Alan Turing and his team deciphered a message indicating that there is going to be an attack on the British Navy. After celebrating for finally able to beat the Enigma Machine made by Germany, they calmed down quickly and decided not to present the message to the British Navy. It's confusing for me at first of why they chose to keep the attack as a secret, but I then understood the importance of keeping some of the messages private for the good of the big picture. It took unimaginable great effort for Turing’s team to figure out how to defeat the Enigma Machine. They can’t risk the chance to let the German Intelligence find out that they cracked the code. If they changed the Enigma Machine into other types of encrypting methods, more damage than a team of warships would be made and the war might have gone in another direction. In special times, some small sacrifices need to be made to win the war.
It’s just like what Admiral Hall did to President Wilson. If they can’t find a source of retrieving the information that they can explain, the Germans will change the encrypting methods, and the British cryptanalysts will lose the advantage. Is it ethical? It’s probably not. However, it’s the war situation; so it needs to be treated differently. Admiral Hall did this so that the American, the most powerful country in the world, can join the Allies and fight German. It’s the war strategy and leads to an acceptable result. When the messages were spread out later, the damage made can be accepted for the privilege of the great world war.
On the other hand, after the Americans joined the Allies, it’s also helping the Americans if they have access to decipher the German messages. Therefore, it’s necessary for Admiral Hall to keep some messages secret. It’s too much to risk as they will lose all of their achievements the fact that they broke the German Code was known.