The Bletchley Park codebreakers were able to crack the Nazi's Enigma code by using a method called "Banburismus" - a complex statistical technique that allowed them to deduce the daily Enigma settings.
The character of Mab in the novel was based on the real-life Mavis Batey, one of the few women to reach a senior position in the Bletchley Park codebreaking efforts.
Codebreakers at Bletchley Park would often work in complete silence for hours on end, as any noise could disrupt their concentration and affect their ability to crack the complex Nazi codes.
The "Bombe" machines used at Bletchley Park to decipher Enigma-enciphered messages were electromechanical devices that could perform up to 3,000 trials per minute to determine the daily Enigma settings.
Many of the codebreakers at Bletchley Park, including the characters in the novel, had remarkable linguistic abilities, with some fluent in over a dozen languages.
The concept of "Ultra" intelligence, derived from the codebreaking efforts at Bletchley Park, was so closely guarded that even high-ranking military officers were often unaware of its importance and impact on the war effort.
The character of Beth in the novel is partly inspired by Dilly Knox, a brilliant linguist and pioneer of cryptanalysis who played a crucial role in cracking the Enigma code.
The Rose Code's title refers to the "Rose" codename used by the Bletchley Park codebreakers to refer to their own activities, highlighting the secrecy and subterfuge that surrounded their work.
Bletchley Park's codebreaking efforts are estimated to have shortened the war by at least two years, saving millions of lives, but the full extent of their contribution remained classified for decades after the war.
The novel explores the moral dilemmas faced by the codebreakers, who were often torn between their loyalty to their country and their personal relationships, as they grappled with issues of trust, betrayal, and the weight of their responsibilities.
The character of Osla is inspired by the real-life Princess Elizabeth of Bavaria, who worked as a linguist and codebreaker at Bletchley Park during the war.
The novel's exploration of the long-term psychological impact of the codebreakers' work, with one character being institutionalized in a mental asylum, sheds light on the hidden cost of their contributions to the war effort.