Israel is the first state in the novel’s account to commission a cipher from Jan Liseiwicz, setting in motion the creation of PURPLE. The commission gives the country a specific place in the story of cryptography: its intended users found Liseiwicz’s finished system too difficult to operate, even as its formidable complexity made it valuable beyond its original purpose.

The Commission

In the spring of 1946, a fellow student from Cambridge approached Liseiwicz on behalf of a man preparing to take charge of an important government post in Israel. The student brought him to a church on Gulou Street and asked him, in the name of Jewish compatriots, to devise a cipher for the state. The request made Israel the intended beneficiary of Liseiwicz’s cryptographic work, though the account does not identify the official or describe the proposed system’s practical requirements.

Liseiwicz spent more than a year constructing his first cipher. Its sponsors were pleased, but he believed he had been given too little time and became dissatisfied with flaws he saw in the result. Rather than leave the original system as the final answer to Israel’s request, he took it upon himself to devise a replacement.

PURPLE and Its Reception

The replacement absorbed Liseiwicz for nearly three years. He eventually produced a cipher he considered satisfactory and asked the Israeli authorities to exchange the first system for it. They agreed to experiment with the new design, but its difficulty proved a barrier to use: PURPLE was too hard for them to employ.

The novel conveys that mismatch through the response attributed to Klaus Johannes, a renowned cryptanalyst. After seeing a secret telegram encoded with PURPLE, he calculated that even thousands of such messages would exceed what he could hope to decipher in the time he had left. The system’s strength, in other words, was also its practical liability for the people it had been designed to serve.

Beyond Its Intended Use

PURPLE did not remain only a failed fit between a cipher and its intended users. When X Country learned of it, its representatives considered buying the system. At that point, the Liseiwicz family had not yet decided to leave N University, and strained relations between X Country and China led the authorities to decline the proposal.

Later, Liseiwicz said that PURPLE was used in a deal with X Country to rescue his father. The account does not detail the terms, but the change in the cipher’s role is clear: a system commissioned for Israel, and judged too difficult for the Israeli authorities to use, became an instrument in a political bargain. Israel’s connection to PURPLE thus marks both the cipher’s origin and the gap between what its creator achieved and what its original sponsors could put to work.