Can the calling method similar to the codebook used in Latency be deciphered?

In many TV movies, we often see such a scene: the commander is standing by the radio station, dictating the information to the sender, while the sender skillfully taps the keys and makes a beep. It's not that you can't send a message. Don't say that. Even if it is possible, it is to send information to the enemy as undercover. Since a message is sent in a certain code, it must have the secret code of this code before it can be restored to text. That is to say, when a telegram needs to be sent, the confidential personnel must first use the password to turn the text content of the telegram into numbers. When receiving a telegram, the receiver also needs to use confidential personnel to restore the sent number to words with passwords. The receiver can only send and receive numbers and doesn't know the contents of the telegram at all. No one except confidential personnel should understand what the undeciphered numbers are, including leaders.