Era of Cryptic Codes

During WWII, your protagonist is a codebreaker deciphering encrypted enemy communications.

Here, the protagonist works in secret, battling time and intellectual puzzles to help the war effort. This should delve into the analytical and emotional journey – the highs of de-coding success, lows of failure, constant pressure, and gradual becoming of an uncelebrated war-hero. How does the protagonist deal with the wartime grimness? How do the broken codes impact the war’s outcome?