NSA (National Security Agency) "Eavesdropping On Hell", by Robert J. Hanyok
Historical Guide to Western Communications Intelligence and the Holocaust, 1939-1945
"There is no river but memory Raise up, raise up a pillar of our tears." Leaving Sodom” by Ann Lauinger
Surely, the grimmest part of the Second World War was the Holocaust (or Shoah). This entailed the systematic and wholesale destruction of European Jewry and other groups such as Slavs, Poles, and Romany (Gypsies), among others, which the Nazis had deemed “inferior” and then slated for destruction because of race, blood, or disability. In fact, one of the major war aims of Nazi Germany was the extermination of global Jewry. During the war years, Europe’s landscape was scarred by the presence of concentration, labor, and death camps. Einsatzgruppen (operations groups), and numerous German Police units roamed the western Soviet Union in the wake of the Wehrmacht, slaughtering Jews, Slavs, and Bolsheviks. Collaborationist regimes of nations allied to or conquered by the Axis powers cooperated with the Nazi security forces in extinguishing national or resident refugee Jewish populations. The darkness that overwhelmed Nazi- occupied Europe and threatened other nations in the world was only slightly lessened by individual acts of courageous opposition and the example of the nation of Denmark, which smuggled virtually its entire Jewish population to safety in Sweden. By the end of the war, it has been estimated that Europe’s Jewish population had been reduced to somewhere between a third to a quarter of its 1939 level. 
In the years following the war, a number of histories, memoirs, and specialized studies about the Holocaust were published. These works were based on a variety of private and official sources that were then available to the public. For the longest period, one element that was largely missing in the historical accounts was the records of the various Western intelligence agencies, such as the American Office of Strategic Services (OSS) and Britain’s M.I.6. Also absent was the intelligence gathered by the wartime Allied communications intelligence (COMINT) agencies, most notably the British Government Code and Cypher School (GC&CS), the U.S. Navy’s OP-20-G, and the U.S. Army’s Signals Intelligence Service (SIS). The revelations in the mid-1970s of the Allied code-breaking successes - the deep and persistent exploitation of Axis codes, ciphers, and communications, popularly referred to as “Ultra” - only whetted the appetite of Holocaust researchers. Once it was known that Allied code- breakers had pierced the Reich’s deepest secrets, the question posed was how much more information would be available for researchers?
Beginning in the mid-1970s, scholars of the Holocaust who had wanted to utilize the archived material of the wartime code-breaking agencies focused their research on the then available records at the United States’ National Archives and Records Administration (NARA) and the United Kingdom’s Public Record Office (renamed the National Archives in 2003). During the first few years after the Ultra revelations, these scholars discovered little significant information about the Holocaust in the wartime records of the British GC&CS and the American SIS. These records, by the way, were stored in the record groups of their modern successor agencies. The records of the SIS were to be found in Record Group (RG) 457, the records of the National Security Agency (NSA). The GC&CS records were placed in Group HW, the records of the Government Communications Headquarters (GCHQ). The actual number of records in either group was not large by any measure; nor were they particularly revealing. For example, in NARA by 1990, there were about 150 translations of intercepted wartime Japanese, German, and Vichy diplomatic messages that referred to the Holocaust, while at the PRO there may have been fewer.  Considering the nature and scope of the Holocaust - every country in Europe and many of their colonial holdings were affected in some fashion by what the Nazis were doing – the number of publicly available records seemed meager.
At the same time, the records that were available seemed to have large gaps in the subject matter that they covered. Topics of enormous importance to understanding the Holocaust, such as the depredations of the police and SS units in Russia, the operations of the death camps, and the roundup of the Hungarian Jews, barely were mentioned in the extant material. Especially when compared to the large body of records from these and other events during the Holocaust, that there were so few items from communications intelligence sources in the British and American archives during the 1970s seemed to invite disbelief, ridicule, or suspicion.
Researchers also could construe the absence of significant archival holdings of the wartime records of the Allied code-breaking agencies to mean that further, still unrealized, caches of records existed. These “absent” records were believed to be in either one of two forms: finished intelligence in the form of reports still classified and therefore withheld from the public, or there existed troves of “raw,” or undecrypted, Axis messages at these agencies. Exacerbating the situation was the publication, during the decade of the 1980s, of the official multivolume History of British Intelligence in the Second World War.  This enormous history referenced British records of intercepted Nazi messages about the Holocaust, mainly those of the German Police who were one of the primary agents for the massacres of hundreds of thousands of Jews and others in the western Soviet Union. The history also referred to intercepted messages from the SS concerning the slave labor populations at a number of concentration camps.  Ironically, the actual records used to write the history still were not accessible by the public.
In a way these scholars were correct in their observations. Even by the late 1980s, the British and Americans still had much World War II cryptologic material to release. It was not until a number of further significant releases of wartime records of the Signal Intelligence Service and the Government Code and Cypher School through the decade of the 1990s that the amount of COMINT material available to researchers of the Holocaust dramatically increased.5 By early 2004, at NARA, over 600 translations and decrypts of various intercepted messages about the Holocaust could be found in the record groups of the National Security Agency. These included some decrypts of German Police messages that reported the massacres of Jews and other groups. Others are messages from mostly diplomatic sources that bear witness to such events as the roundup of Jews in Hungary and other countries in occupied Europe. At the PRO, the complete set of German Police and SS decrypts were available to be reviewed by the public. 
Even with the releases of the 1990s, the U.S. government still held back significant collections of U.S. government records about the Holocaust. But the remaining wartime records, and those from the postwar period that relate to the Holocaust and to Nazi and other Axis power war crimes will soon be declassified and released thanks to the efforts of the United States Interagency Working Group on Nazi War Crimes (IWG). Established in January 1999 in accordance with the Nazi War Crimes Disclosure Act (P.L. 105-246), the IWG was charged with locating, inventorying, and recommending for declassification all classified Nazi war criminal records held by the United States government. The act was amended in 2000 to include declassification of U.S. government records pertaining to Japanese war crimes and war criminals.  Many of the records that were released under the aegis of the Disclosure Act were from U.S. intelligence agencies. Hopefully, the release of these records will help dispel those claims and charges made over the years by some scholars and Holocaust survivors that “there had to be more records” or that the intelligence agencies were “holding back records.” 
To this historian, the problems that researchers and scholars of the Holocaust had had over the years with the number of available COMINT records appeared to lay elsewhere than just with the paucity of this material. Similar reactions to the later several releases of wartime records to the NARA and the PRO suggested to me that the issue was a fundamental one: That researchers and scholars still misunderstood the basic operation of the Allied wartime COMINT system. Many people did not understand how the wartime code-breaking agencies procured, processed, and disseminated communications intelligence. They did not realize that there were technical and institutional constraints and limitations under which GC&CS and SIS operated. Also, it was not generally well understood that there were priorities established for collection and decryption of Axis and neutral communications and that higher authorities in Allied intelligence and military operations had set these.
Many people also did not know that the operational needs of these agencies largely determined what wartime records were retained after the war, how the existing records were controlled, where the relevant records resided in various national archival collections, and who was responsible for their release. In short, the story of COMINT records relating to the Holocaust is much more than a simple matter of the number of pages available to the public at various national archives.
In considering all of the above, I determined that a historical guide would be useful for researchers, scholars, and the general public. Such a guide could help Holocaust researchers gain a better understanding of how Allied communications intelligence reported intelligence on the Holocaust. It would explain the variety of material that would be encountered in the records of the wartime cryptologic agencies. This guide, then, will concentrate on three topics that would be of interest and utility to scholars and the general public. First, it explains how the Western communications intelligence system operated during the war. It will consider how well the system operated and what were its limitations. This latter point is important when considering how Western COMINT handled intelligence about the Holocaust. Second, the guide describes how the wartime records of the SIS and GC&CS currently are organized in the national archives of Great Britain and the United States, where these records can be found, and the various formats they come in. Third, the guide summarizes what information is available from SIGINT records about the Holocaust. This summary consists of both a general chronology of the Holocaust and selected incidents for which significant communi- cations intelligence records are available.
Despite the scope and detail of some of the material contained in this guide, it is not intended as a narrative history of the Holocaust based on the records of Western communications intelligence agencies. The major reason is that the archived COMINT records cannot sustain such a history. There are too many important parts of the history of the Holocaust for which no communications intelligence was collected. As will be demonstrated later in this work, communications intelligence could not reveal high-level Nazi policy deliberations regarding the Jews and other groups. On occasion, communications intelligence could “tip off’ an impending action by Nazi security forces, as in Italy in the fall of 1943. But this advantage was rare. More often, COMINT was best as a chronicle of some campaigns that already were under way such as the massacres carried out by the German Police units in the western USSR in 1941 and the roundup of the Hungarian Jews in mid-1944.
Although something of a historical narrative of the Holocaust is presented in the last chapter of this guide, it is meant to be a selected summary of the available information from COMINT records. It is beyond the scope and means for historians of cryptology to rewrite the story of the dreadful events of the Holocaust. Their mission is to dis- cover the relevant records and write the history of cryptology and place that story within the context of larger events of the Second World War. It remains for historians of the Holocaust to utilize completely within their narratives the historical information provided by the records of the Allied code-breaking agencies.
This guide will limit its focus to the two major Western COMINT agencies that produced intelligence about the Holocaust during the war: the British GC&CS and the U.S. Army’s SIS. Early in the war, the U.S. Navy’s cryptologic element, OP- 20-G, contributed some intercept of diplomatic communications, but by mid-1942, it ceded this work completely to the SIS and concentrated almost exclusively on Axis naval communications. A number of smaller Allies contributed to the overall Western radio intelligence work. These included Canada, Australia, New Zealand, and others. However, the American and British security concern to protect Ultra sometimes circumscribed the contribution of these smaller allies. Among these, refugee Polish cryptologists contributed major intercept and code-breaking efforts against German Police communications. Their work will be discussed later in the guide.
It is important to mention that the British had a limited COMINT relationship with the Soviet Union. Among other things, this included an exchange of technical information on German Police ciphers. (But it stopped short of revealing the Enigma breakthrough.) The Russians certainly were in a position to intercept more police messages than the British (or the Poles). And they were able to read the same German Police messages as the British. But Western researchers do not know to what extent and for how long the Russians were able to exploit German Police radio traffic. Also, it is not known if the Soviets retained these decrypts in their archives after the war. These uncertainties mean that this guide will forego any consideration of the Soviet contribution to communications intelligence about the Holocaust. This subject must await future researchers gaining access to the appropriate archives in Moscow. 
The background chapter to this guide offers brief summaries of the history of anti-Semitism in the West and the early Nazi policies in Germany, as well as a short review of the limited body of historical and memoir literature prior to 1997 that pertains to both cryptology and the Holocaust. Chapter 2 will describe the general system by which communications intelligence was produced by the Allies during World War II. This description will encompass the system from the establishment of collection priorities, through the intercept of targeted Axis and neutral communications, next to the processing or analysis of the intercept for intelligence, and finally to the dissemination of the produced intelligence. Just as importantly, this section includes observations on how the nature of the communications intelligence process affected the collection of information concerning the Holocaust. Chapter 3 will list the various locations for relevant records of the American and British cryptologic agencies held by the National Archives and Records Administration and the Public Record Office. This chapter will also include a description and some examples of other smaller relevant records holdings. Chapter 4 will briefly review the available COMINT material that is part of the historical narrative of the Holocaust. This chapter includes a brief overview of the course of the Holocaust and somewhat more detailed descriptions of specific topics that include the refugee problem and Palestine, Vichy and the Jews, the roundup of the Hungarian Jews, the situation of the Jews in the Far East under the Japanese, and German-Swiss trade and financial transactions during the war. Finally, Chapter 5 considers some important general observations about cryptology and the Holocaust. In a way, these observations are a summation of the material presented in the guide.
A Note on Terminology
Since the first revelations of the Ultra secret in the mid-1970s, the public has been exposed to a number of arcane terms associated with the business of making or breaking codes. Unfortunately, there has been a tendency among many scholarly and popular writers and reporters to confuse or mix terms. This misuse of terms often led to some inaccuracies in their texts such as referring to the German Enigma machine as a “code machine.” Although most of these terms are not relevant to this work, a few necessarily have to be used to accurately describe various activities and items of the Allied communications intelligence system. So I will define the most important ones and explain how they are used in this monograph.
COMINT is the acronym for communications intelligence and can be defined as measures taken to intercept, analyze, and report intelligence derived from all forms of communications. This definition describes most accurately the entire Western system to exploit Axis communi- cations. The COMINT system included the code- breaking centers at Bletchley Park in Great Britain and the American centers at Arlington Hall, Virginia, and Nebraska Avenue in Washington, D.C. It also includes the monitoring stations manned by Allied radio operators that listened in and copies Axis and neutral radio transmissions. It further covers the work of the various Allied staffs and units that took the analyzed messages, picked out the intelligence that mattered and forwarded it to whatever Allied command, ministry, department, or leader that would need it.
A similar term, signals intelligence, or SIG- INT, is often used synonymously with communications intelligence in many histories of wartime intelligence. Signals intelligence is a term that encompasses a much broader category of electromagnetic emissions than just those used for communications. This category includes such emissions as radar and navigation beacons. During World War II, Western technical intelligence took an active interest in collecting such signals used by the Axis so that countermeasures could be developed against them. The famous British “window,” or chaff (strips of aluminum that reflected radar signals and created interference on German radar screens) was an effective weapon against German warning radars during the Allied bomber offensives. The British employed technical deceptive measures to defeat the Germans navigational beacons used by the Luftwaffe to guide its bombers during night raids against British cities. 
Cryptology is defined as the study of the making and breaking of codes and ciphers. Cryptography is the development of codes and ciphers. A code is defined as a method in which arbitrary groups of letter, number, or other symbols replace words, phrases, letters, or numbers for the purposes of concealment or brevity. To encode is to transform plaintext into a code. To decode is to break a code back to its underlying plaintext. A cipher is a method of concealing plaintext by transposing letters or numbers or by substituting other letters or numbers according to a key. A key is a set of instructions, usually in the form of letters or numbers, which controls the sequence of the encryption of text and the decryption of cipher back to the original plaintext. Transforming plaintext into cipher is called encryption. Breaking the cipher back to plaintext is called decryption. Cryptanalysis is the analytic method whereby code or cipher is broken back to the underlying plaintext. Traffic analysis is the method by which intelligence is derived from the analysis of the communications activity and elements of messages short of the actual cryptanalysis of a message.
Above: Enigma Machine (Courtesy of National Security Agency)
Two examples of famous ciphers from World War II are the Axis cipher machines, the German Enigma and the Japanese Purple (known to the Japanese as the 97-shiki O-bun In-ji-ki, or Alphabetical Typewriter ’97). Both machines substituted letters for plaintext elements according to daily settings (key) for each machine. Interestingly, most ciphers used by all sides during the war overwhelmingly were manual in nature. That is, they involved the use of paper charts and key.
Above: Purple Analog (Courtesy of National Security Agency)
Such a manual cipher was the double transposition cipher used by German Police units to encrypt their reports about the massacres of Jews, partisans, prisoners, and Soviet commissars to Police headquarters in Berlin. Codes used during the war usually came in the form of a book. On each page of the codebook, a plaintext word or phrase was
aligned opposite its code group equivalent. Examples of a code include that used by the Soviets for its espionage messages known through the Allied cover name as Venona and the Japanese operational naval code, JN-25. Both codes utilized books of code values for plaintext, but added an additional element: key, in the form of groups of numbers that were used to encrypt the code groups, further concealing the “true” code groups. This practice made decoding even more difficult: before a cryptanalyst could recover the plaintext value behind a code group, he or she first had to recover the true code group. An example of an ordinary code used during the war was the so-called “Black Code” used by the United States Army military attachés. This system was exploited by both Italy and Germany to great effect in 1941 and was probably Field Marshall Erwin Rommel’s best source of intelligence during the battle for North Africa.11
To facilitate the understanding of readers who may be uncertain of the above jargon or unconformable with it, I will use terms like “cryptology,” “communications intelligence,” “COMINT,” “signals intelligence,” and “SIGINT” interchangeably either as adjectives or as nouns by which to describe or identify the overall system the Allies used to exploit Axis cryptography and communi- cations. Using these five terms as general descriptors will not sacrifice accuracy and probably will make the text more readable. Other terms from cryptology, used once, will be defined as they are encountered in the text.
This guide took over five years to complete, far longer than originally planned when I began in late 1998. Why did it take so long to finish? Initially, like many other historians of cryptology, I believed that there was not much material avail- able and felt therefore that a guide could be published within a relatively short time. In 1999 I previewed the guide in a paper delivered at the Cryptologic History Symposium held at Fort George G. Meade, Maryland. At the time I felt that relevant record sources mostly had been examined by scholars. A review of the symposium paper in an intelligence journal had emphasized my remark about the “scanty” amount of communications intelligence records.”12 But I was wrong. The Interagency Working Group (IWG) on Nazi War Crimes (that soon included Imperial Japanese Imperial Records), which I joined in early 2001 as a technical advisor to its staff, already was deep into an extensive review all the records of Nazi crimes held by the many agencies and departments of the United States government, including its intelligence agencies. The records that were unearthed by the various intelligence agencies, and the clues they provided to supplementary finds in the British Public Record Office and the U.S. National Archives, indicated that there were many more pages of cryptologic records than earlier believed. Every further meeting of the IWG and the associated Historical Advisory Panel I attended had uncovered more records. I realized I had to delay the completion of this guide until the search by the IWG neared completion. The wait, I believe, was well worth it.
Within the National Security Agency, there were many people who contributed their efforts, directly and indirectly, to the publication of this Guide. First of all, the Publications Team of the Center for Cryptologic History (CCH) did its usual magic and turned my initial “heap of words” into the presentable form it now is. Many thanks go to the tireless efforts of Lula Greenwood and Barry Carleen. Within the CCH, Dave Mowry, Sharon Maneki, and David Hatch reviewed my manuscript and offered many useful points. Elsewhere, I am grateful for the insights from Robert L. Benson and Rona Lerner. There were others who contributed to this guide from the NSA, yet they cannot be mentioned by name. I wish to thank them publicly for their help.
Because of the scope of the information in this guide, it was necessary to consult with many individuals outside of the NSA. Although personal research provided much historical background to the Holocaust, the many months that I spent reviewing the literature of the Holocaust could not provide me with that astute insight that is gained only from a deep and sustained professional study of a subject. So I queried a number of academic historians, independent scholars, and researchers familiar with the Holocaust for help. In all of my correspondence with them, I encountered nothing but gracious and full cooperation. My questions were patiently and quickly answered, requests for material were filled promptly, and several people took time from their busy schedules to review the manuscript. I hope that our effort was a mutually rewarding learning experience. Their cooperation suggests that history is more than a mere academic discipline; at times it can be a true community of effort, even, if at times, it can be a bit contentious. With this experience in mind, I wish to thank the following people for their incisive and useful comments on my manuscript: Gerhard Weinberg, Richard Breitman, Rebecca Boehling, Colin “Brad” Burke, David Alvarez, Christopher Lovett, Sebastian Laurent, Miriam Kleiman, and Ron Zweig. A very special thanks go to Stephen Tyas, Ralph Erskine, and Rebecca Ratcliff for both their comments on the manuscript and for sharing their historical research from the Public Record Office. And a final thanks to the archivists of the U.S. Holocaust Memorial Museum in selecting images from their photographic archives.
If there are any errors in this guide, then, in the eloquent words of the Qur’an: “If I err, I err just on my own.”
Robert J. Hanyok Fort George G. Meade, MD 2005
1. Precise figures for the destruction of European Jewry are difficult to arrive at. Among other reasons, poor national census bases, a reluctance by some European nations to account for Jewish losses, and an uncontrolled refugee flow during and after the war have contributed to the continuing imprecision and discrepancies in the estimates. Most statistics are, in reality, good estimates. One source is Leon Poliakov and Josef Wulf, eds, Das Dritte Reich and die Juden: Dokumente und Aufsaetz (Berlin: Arani-Verlag GmbH, 1955). The Jewish population of September 1939 Europe is estimated at 8.3 million. The number of Jews murdered is put at 5.97 million or about seventy-two percent. Another source, Wolfgang Benz in Dimension des Volksmords: Die Zahl der Judischen Opfer des Nationalsocialismus (Munich: Deutscher Taschebuch Verlag, 1991) places the final toll at 6.26 million Jews.
2. In the U.S. National Archives, some of the records in RG 457, “The Records of the National Security Agency/Central Security Service,” can be found both the original version and a “redacted” version. This confusing situation resulted from the stricter requirements for declassification of the material released in the mid-1980s. By the mid-1990s, many of the earlier restrictions had been eased and original version of some of the material from the initial releases was transferred to the Archives without any deletions. Good examples of these dual versions can be found by comparing redacted Japanese translations found in Entry 9011 (notated also as “SRDJ”), or redacted French Vichy diplomatic translations, Entry 9021 (notated also as “SRDV) with the original, unredacted translation that can be found in the Historical Cryptographic Collection, Boxes 286 to 516.
3. F. H. Hinsley, et alia, British Intelligence in the Second World War: Its Influence on Strategy and Operations. (Volumes I-III) (London, Her Majesty’s Stationery Office, 1980 to 1990) Volume IV. F.H. Hinsley and C.A.G. Simkins, Security and CounterIntelligence (1990). Volume V. Michael Howard, Strategic Deception (1990).
4. Hinsley, Volume II (Appendix 5), 669-73.
5. For example, in 1996 the National Security Agency released some 1.3 million pages of World War II records to the National Archives. This material was placed in the Historical Cryptographic Collection (HCC). The records originated with the U.S. Army’s cryptologic agency known primarily as the Signals Intelligence Service. In this release were German Police messages and many more diplomatic messages from other countries, such as Switzerland and the Vatican, which referenced the Holocaust.
6. The numbers may yet change. At the PRO, there are a substantial number of GC&CS diplomatic translations still to be released to HW 12. Also, at NARA in RG 457, HCC, there are numerous boxes of so-called “Summary Translations” that consist of single pages with several short diplomatic translations. A single sheet can contain as many as five short translations, some of which are relevant to the Holocaust. (See Chapter 4 for an example of one of these “Summaries.”)
7. Although a final count of records released under the Act remains to be made, as of January 2004, almost 700,000 pages from the Central Intelligence Agency, the Federal Bureau of Investigation, the National Security Agency, and the U.S. Army had been released. It is expected that the IWG will release three volumes of reports in 2004-5. There will be an overall report on the working group and its collaboration with other federal agencies. There also will be two volumes of reports by IWG-associated historians about the nature and significance of the declassified and released records. One volume will cover Europe while the other will consider Asia and the Pacific.
8. This historian personally encountered such charges, as well. At a NARA-sponsored symposium on Records and Research relating to Holocaust-era Assets in December 1998, a colleague from CIA and I were confronted by several Holocaust survivors who angrily claimed that our agencies were withholding records about certain Nazi war criminals. As it turned out, they had recently received negative responses to Freedom of Information Act requests concerning specific war criminals. They believed that NSA and CIA were withholding records on these individuals.
9. For further information see Hinsley, Vol. II, 57- 65 and Bradley F. Smith, Sharing Secrets with Stalin: How the Allies Traded Intelligence, 1941-1945 (Lawrence KS: University Press of Kansas) 1996, 109-111. Aspects of the proposed early British COMINT liaison with the Soviet Union can be found in PRO, HW 14/18, August 1941.
10. Probably the most complete and entirely read- able book on the subject remains R.V. Jones’s The Wizard War. British Scientific Intelligence, 1939-1945 (New York: Coward, McCann & Geoghegan, Inc., 1978).
11. See David Kahn, Hitler’s Spies: German Military Intelligence in World War II (New York: Macmillan Publishing Co., 1978), 193-5, and The Codebreakers (New York: The Macmillan Company, 1967), 472-4; Bradley F. Smith, The Ultra-Magic Deals And the Most Secret Special Relationship, 1940- 1946 (Novato, CA: Presidio Press, 1993), 111-112. For a description of U.S. diplomatic codes and ciphers during the period, see Ralph E. Weber, United States Diplomatic Codes and Ciphers, 1775-1938 (Chicago: Precedent Publishing Co., 1979), 250-254.
12. Ralph Erskine. “Three Conferences.” International Intelligence History Association (Vol. 7, No. 2, Winter 1999). The paper also is mentioned in James Bamford’s Body of Secrets: Anatomy of the Ultra-Secret National Security Agency from the Cold War through the Dawn of a New Century (New York: Doubleday, 2001), 10-11.
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