More information from ‘It Wasn’t All Magic’

The recently released United States Cryptologic History: ‘It Wasn’t All Magic: The Early Struggle to Automate Cryptanalysis, 1930s – 1960s’ has some interesting information in pages 266-7 regarding the Japanese Purple cipher machine and the Soviet Longfellow cipher teleprinter.

Purple was used by the Japanese Foreign Ministry since the late 1930’s but after the war it seems that it continued to serve the Emperor! Apparently this time it was used to generate random diplomatic one-time pads. According to the report: ‘Somewhat later, Japan's reintroduction of the Purple machine to generate one-time pads for its diplomats proved quite useful to America's SIGINT monitors.’

The Soviet Longfellow cipher teleprinter was such an important target for the American codebreakers that very advanced cryptanalytic equipment was built to decode its messages:

‘Much more ambitious was Hiawatha. In late 1947 electronic potentials finally came together with a cryptanalytic opportunity to force the release of massive funding for the long-sought Electronic Super Bombe. The elusive electronic matrix finally seemed ready, and at the same time enough had been learned about Longfellow to think that a bombe would allow continuous reading of its messages.’

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‘The attack on Longfellow was thought to be just a prelude to reading the rest of Russia's most valuable communications. The Cold War, it seemed, was to have its own Ultra.’

Unfortunately this breakthrough could not be taken advantage of because the Soviets removed Longfellow from service in 1948!

‘Howard Campaigne, was furious with the Americans as well as the Soviets. When he learned that ERA's electronic bombe project was terminated, he wrote: "If we had complete coverage [of Longfellow] from the beginning [1943] we probably could have been reading their communications by 1945. If we had supported this by the analytic machinery recently planned, we could have broken out most of the available traffic. The entire story is one of 'too little too late'. This system was in use for five years, yet we were not ready to read it in quantity until it disappeared."

 If Campaigne is right and Longfellow was introduced in 1943 then it must have been the machine the Soviets called M-101.