Robert J. Hanyok


Hanyok, Robert J. "'Catching the Fox Unaware': Japanese Radio Denial and Deception and the Attack on Pearl Harbor." Naval War College Review 61, no. 4 (Autumn 2008): 99-124.

"The completeness of the operational surprise [at Pearl Harbor] ... was due largely to the success of the Japanese cover plan of radio denial and deception in hiding the existence, makeup, purpose, and timing of the attack." Japanese planners "developed a synchronized plan for the Pearl Harbor Striking Force that combined the three elements of radio silence, active radio deception, and radio intelligence in a way that assured Tokyo that the U.S. Pacific Fleet was unaware of the approaching Kido Butai." In essence, "the Japanese convinced American intelligence that their carriers, the spear point of the Imperial Japanese Navy, were still in the home islands on 7 December 1941."


Hanyok, Robert J. Eavesdropping on Hell: Historical Guide to Western Communications Intelligence and the Holocaust, 1939-1945. Ft. George Meade, MD: National Security Agency, Center for Cryptologic History, 2005. [Available at:]

Aftergood, Secrecy News (from the FAS Project on Government Secrecy) 2005, no. 54 (8 Jun. 2005), refers to this work as a "major historical study of communications intelligence (COMINT) regarding the destruction of European Jewry and other targeted populations during World War II."

For Alvarez, I&NS 20.4 (Dec. 2005), "[t]his is a superb monograph" that "provides an informed overview of how American and British communication intelligence (Comint) agencies reported the Holocaust.... Those seeking a short [167 pages] but authoritative account of codebreaking and the Holocaust need look no further." Wolfe, Cryptologia 33.4 (Oct. 2009), calls this book "an interesting read, filled with facts and specific examples of decrypted intercepts. It contains an invaluable set of references for the reader who is interested in pursuing the topic."

[UK/WWII/Ultra; WWII/Gen & Magic/Gen]

Hanyok, Robert J. "Skunks, Bogies, Silent Hounds, and the Flying Fish: The Gulf of Tonkin Mystery, 2-4 August 1964." Cryptologic Quarterly 19, no. 4/20, no. 1 (Winter 2000-Spring 2001): 1-55. []

The author calls this narrative "the complete SIGINT version of what happened in the Gulf of Tonkin between 2 and 4 August 1964." This "new version ... is based on the discovery of an enormous amount of never-before-used SIGINT material." This material tells "a different story": no North Vietnamese attack occurred on 4 August 1964. Hanyok also maintains that "only SIGINT that supported the claim that the communists had attacked the two destroyers was given to administration officials."

Lloyd R. "Joe" Vasey [RADM/USN (Ret.)], "Tonkin: Setting the Record Straight," U.S. Naval Institute Proceedings 136, no. 8 (Aug. 2010), 71, argues that "there are serious flaws in Hanyok's analysis."


Hanyok, Robert J. Spartans in Darkness: American SIGINT and the Indochina War, 1945-1975. Ft. George Meade, MD: National Security Agency, Center for Cryptologic History, 2002. []

Aftergood, Secrecy News, 7 Jan. 2008, notes that this work is "an exhaustive history of American signals intelligence (SIGINT) in the Vietnam War.... Hanyok[] writes in a lively, occasionally florid style that is accessible even to those who are not well-versed in the history of SIGINT or Vietnam." See also, Peter Grier, "Declassified Study Puts Vietnam Events in New Light," Christian Science Monitor, 9 Jan. 2008.

[NSA/Sigint; Vietnam/Gen]

Hanyok, Robert J., and David P. Mowry. West Wind Clear: Cryptology and the Winds Message Controversy -- A Documentary History. Ft George G. Meade, MD: Center for Cryptologic History, National Security Agency, 2008.

This "volume contains all of the standard, critical documents." It "also includes many documents that have not been seen before, such as the U.S. Navy's translation and cryptanalytic worksheets of the 19 November 1941 Japanese Winds instruction messages, and the translation worksheets of the Federal Communications Commission from early December 1941." This is "really a documentary history of the [Winds] controversy, is intended to make available to all sides the basic sources: the worksheets and the translations of the pertinent Japanese diplomatic correspondence, the logs and chronologies of events, the pertinent correspondence amongst the major players, and associated memorandom and notes." (x-xi)

Booker, Cryptologia 34.1 (Jan. 2010), argues that the authors "prove, beyond any doubt, that the Winds message was not the indicator of the attack on Pearl Harbor and was not broadcast until after the attack.... [T]he Winds message controversy can finally be laid to rest with this study."


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