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Hans-Thilo Schmidt (13 May 1888 – 19 September 1943) codenamed Asché or Source D, was a German spy who sold secrets about the Enigma machine to the French during World War II. The materials he provided facilitated Polish mathematician Marian Rejewski's reconstruction of the wiring in the Enigma's rotors and reflector; thereafter the Poles were able to read a large proportion of Enigma-enciphered traffic. He was the younger brother of Wehrmacht general Rudolf Schmidt.

Key Information

Selling Enigma secrets

[edit]
Rodolphe Lemoine [fr], born Rudolf Stallmann (1871–1946), served as his French point of contact as "Rex".

A former officer, Schmidt had been forced to leave the army having suffered from gas during the First World War.[1] His brother, Rudolf Schmidt, secured him a civilian post at the German Armed Forces' cryptographic headquarters, the Cipher Office.[1] Shortly after the military version of the Enigma machine was introduced, he contacted French intelligence and offered to supply information about the new machine. His offer was accepted by Captain Gustave Bertrand of French Intelligence, and he received from the French the codename Asché, and was assigned a contact, the French agent codenamed Rex.

For the next several years, until he left his position in Germany, he met with French agents at various European cities and supplied them copies of the Enigma machine's instruction manual, operating procedures, and lists of key settings. Even with this information, however, French Intelligence was unable to break messages encrypted on the Enigma. Nor were the British cryptologists whom Bertrand contacted able to make any headway.

In December 1932, Bertrand shared intelligence obtained from Asché with the Polish General Staff's Cipher Bureau (Biuro Szyfrów). Mathematician-cryptologist Marian Rejewski had already set up a system of equations describing the operation of the then new German Army Enigma rotor-wirings. The key-settings lists provided by Schmidt helped fill in enough of the unknowns in Rejewski's formulae, allowing him to speedily solve the equations and recover the wirings. That accomplished, the Poles were henceforth able to read Enigma traffic for nearly seven years to the outbreak of World War II as well as for a time into the War, while operating in conjunction with French intelligence in France. In a two-week January 1938 trial, they solved and read about three-quarters of all Wehrmacht (German Armed Forces) Enigma intercepts: a remarkable result, considering that parts of the raw intercepts were garbled or incomplete due to interference [Kozaczuk, Enigma 1984, p. 45].

After the Battle of France, the French agent who had been Schmidt's case officer, a German citizen named Stallmann who went by the name "Rodolphe Lemoine" (fr) and used the codename "Rex," was arrested by the Gestapo and betrayed Schmidt as a French spy. Schmidt was arrested on 1 April 1943, and in September 1943 his daughter Giselle was called on to identify his body; her account (as recounted in Hugh Sebag-Montefiore's book) suggests that Schmidt had committed suicide.

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Hans-Thilo Schmidt

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Hans-Thilo Schmidt (13 May 1888 – 19 September 1943), codenamed Asché by his French handlers, was a German civil servant employed in the Reichswehr's cipher office who spied for French intelligence from 1931 until his capture in 1943, primarily motivated by personal financial desperation. Positioned through family connections—his brother Rudolf was a prominent general—Schmidt accessed and photographed highly classified documents, including Enigma machine operating manuals, wiring diagrams, and monthly key settings, which he delivered to French agents in exchange for payments totaling tens of thousands of Reichsmarks. These materials, shared by France with Polish cryptanalysts in 1932, enabled the reconstruction of Enigma's internal mechanisms and partial key recovery methods, providing the foundational intelligence that British codebreakers at Bletchley Park later expanded into systematic decryption of German Wehrmacht and naval signals throughout World War II. Despite the espionage's profound strategic impact—contributing to Allied victories in key campaigns like the Battle of the Atlantic—Schmidt's activities evaded detection for over a decade due to lax German counterintelligence, until a routine Abwehr audit in 1943 exposed his double life, leading to his arrest, conviction for high treason, and execution by guillotine at Plötzensee Prison.

Early Life and Background

Family Origins and Childhood

Hans-Thilo Schmidt was born on 13 May 1888 in , then part of the , into an upper-middle-class family with academic and noble ties. His father, Dr. phil. Rudolf Hermann Schmidt (1851–1936), served as a university history professor, holding the prestigious title of Professor Doktor that reflected scholarly distinction in Wilhelmine . His mother, Johanna Elisabeth Francisca Agnes Udine von Könitz, descended from baronial lineage, adding an element of minor aristocracy to the household. Schmidt was the younger son, with his older brother (1886–1957) later achieving the rank of general in the , a connection that would influence Hans-Thilo's access to military circles. Details on his childhood remain sparse in historical records, but the family's educated milieu in —amidst the empire's intellectual and bureaucratic elite—provided a foundation conducive to civil service ambitions, though Schmidt himself pursued before injuries altered his trajectory.

Education and Initial Employment

Schmidt pursued training as a chemist following his service in the German military during World War I. In the postwar years, economic instability hindered his ability to secure suitable employment in chemistry, leading to financial dependence on his wife Charlotte Speer's family business, C.A. Speer, which eventually closed due to broader downturns. By the late , leveraging familial ties—particularly his brother Rudolf Schmidt's tenure as head of the Cipher Office from 1925 to 1928—Hans-Thilo obtained a civilian position in the German Defence Ministry's Cipher Office (Chiffrierstelle) in , initially as an assistant to Major Oschmann, marking his entry into government cryptographic administration.

Career in the German Government

Civil Service Positions

Hans-Thilo Schmidt, having experienced financial difficulties and unemployment following , secured entry into the German through nepotistic channels in the late . His elder brother, —a colonel in the and former director of the Cipher Office (Chiffrierstelle) from 1925 to 1928—recommended him for a position as trusted assistant to the office's new head, Major Erich Oschmann, around 1928. In this mid-level role within the Ministry's Cipher Office in , Schmidt handled administrative tasks involving cryptographic materials for the armed forces, granting him access to a secure safe containing sensitive documents. The appointment reflected the era's reliance on personal networks in Weimar-era , where familial ties often trumped merit amid post-Versailles Treaty constraints on military staffing. By the early , amid Nazi consolidation of power, Schmidt transitioned to another post in the newly established Research Office (Forschungsamt) of the Reich Air Ministry, a unit focused on intercepting communications, including those from foreign embassies and internal dissenters. This move expanded his purview beyond ciphers to broader operations, though his core expertise remained rooted in cryptographic administration.

Involvement with the Cipher Office

Schmidt obtained a civilian clerk position at the Chiffrierstelle, the Reichswehr's cryptographic office responsible for developing and distributing ciphers including the , through his elder brother , a high-ranking officer who later commanded the bureau. This appointment followed Schmidt's financial setbacks from failed business ventures in the mid-1920s, providing him stable employment in Berlin's Defense Ministry. In his role, Schmidt managed administrative tasks involving key allocation, procedural manuals, and communication protocols for systems. By 1931, at age 43, he functioned as an executive-level employee with access to daily and monthly Enigma settings, wirings, and operational instructions, reflecting the trust placed in him due to familial connections. The Chiffrierstelle's work centered on securing transmissions amid post-Versailles rearmament, where Schmidt's duties included safeguarding and disseminating materials that ensured the confidentiality of high-level orders. Schmidt remained in the Chiffrierstelle through the early , contributing to the office's expansion under Nazi oversight, before transitioning to related roles. His tenure highlighted the bureau's reliance on civilian expertise for cryptographic administration, though internal vulnerabilities arose from personal motivations among staff.

Espionage for France

Motivations and First Contacts

Hans-Thilo Schmidt's motivations for were predominantly financial, stemming from an extravagant lifestyle that outpaced his salary. Despite employment in the German Defense Ministry's Cipher Office, Schmidt supported multiple mistresses and indulged in personal luxuries, exacerbating debts amid Germany's in the early . Unlike ideologically driven spies, Schmidt's actions lacked patriotic or anti-Nazi sentiment, prioritizing monetary compensation over principle. In late 1931, facing acute financial strain, Schmidt initiated contact with French intelligence by volunteering his services at the French embassy in Berlin, offering to sell classified documents from the Cipher Office. This approach, made around November 1, 1931, prompted French verification of his access and credibility, leading to his recruitment under the codename "Asché." Initial handling was assigned to agent Rodolphe Lemoine (alias "Rex"), who met Schmidt in neutral locations like to receive materials, beginning with Enigma operating instructions on December 27, 1931. French intelligence, under Gustave Bertrand, quickly recognized the value of Schmidt's position near his brother Rudolf, a senior officer, and established a payment structure scaling with document sensitivity. Hans-Thilo Schmidt initiated the delivery of Enigma-related materials to French intelligence in , beginning with a meeting on November 8 in , , where he handed over documents including the Enigma instruction manual that detailed rotor wirings and setup procedures. These materials, obtained from his position in the German Cipher Office, were photographed by French agent Rodolphe Lemoine, who served as the handler, under the oversight of cryptologic chief Gustave Bertrand. Subsequent deliveries included tables of daily keys; by the end of 1932, Schmidt provided Bertrand with key settings for multiple months, enabling insights into the machine's operational configurations. The transactions occurred through clandestine meetings, with Schmidt selling the classified items for , motivated by personal debts. French records confirm that the provided manuals pertained to the military Enigma variant, though initial versions predated some modifications, limiting immediate decryptive utility without further analysis.

Scope of Intelligence Provided

Schmidt's espionage activities, spanning from 1931 until his arrest in 1943, primarily centered on German military cipher systems, with a focus on the Enigma machine employed by the Reichswehr, alongside broader intelligence on rearmament and operational plans. As a civil servant in the German cipher office with access facilitated by his brother Rudolf Schmidt's senior military role, he supplied French intelligence—via agent Rodolphe Lemoine—with photographic copies of sensitive documents, motivated chiefly by financial gain rather than ideology. His deliveries included operational manuals, key settings, and procedural guides, enabling initial French and subsequent Polish cryptanalytic efforts, though the French Deuxième Bureau under Gustave Bertrand often failed to fully exploit the materials due to resource limitations. The core of Schmidt's Enigma-related intelligence comprised technical and operational documents leaked starting in 1931. These included the Enigma user manual, enciphering procedures with accompanying drawings, and setup instruction booklets detailing machine configuration for encoding messages. In 1932, he provided the operating manual during a clandestine meeting in , along with daily keys and settings tables, which lacked rotor wiring diagrams but allowed reconstruction of the machine's internal logic by Polish cryptologists and his team after the French shared the materials in December 1931. Subsequent provisions of routine daily Enigma ciphers extended into the late , offering glimpses into communications patterns, though outdated keys were sometimes included at Polish request via French intermediaries. Beyond Enigma specifics, Schmidt's leaks encompassed wider military and strategic disclosures, reflecting his access to high-level materials. In , he revealed details of programs, including troop deployments and equipment inventories, as well as Nazi expansionist intentions evidenced by a 1938 map projecting conquests through 1948. He also exposed activities of the Forschungsamt, Hermann Göring's arm, which by 1937 had intercepted French embassy communications in and cracked several diplomatic codes, compromising Allied secrecy. A critical late provision came in March 1940, when Schmidt warned of an imminent German offensive through the in spring, a rooted in operational orders but dismissed by French command despite its accuracy in foreshadowing the assault. These non-cipher elements, often delivered in bulk as cases of documents, underscored Schmidt's role as a prolific source, though their strategic underutilization highlighted French shortcomings.

Capture, Trial, and Execution

Rising Suspicions

In the wake of the German occupation of in , the systematically dismantled remnants of French intelligence networks, arresting key figures involved in pre-war operations. Rodolphe Lemoine, a French agent operating under the alias "Rex" who had served as Hans-Thilo Schmidt's primary contact since 1931, was captured in and subjected to interrogation. Under pressure from tactics, Lemoine confessed to handling a high-level German source and identified Schmidt as the individual who had supplied critical documents on German military ciphers, including Enigma settings and procedures, over more than a decade. This revelation shifted immediate suspicion toward Schmidt, a civil servant in the German Ministry of Defense's cipher office, whose access to such materials had enabled the leaks. German counterintelligence cross-referenced Lemoine's testimony with known intelligence failures, such as the early Allied insights into Enigma wiring and daily keys provided to Polish and French cryptanalysts in , confirming the scope of the breach. Although Schmidt had maintained a facade of and his financial motivations—stemming from business failures and debts—had not previously triggered formal audits, the direct naming by Lemoine prompted swift surveillance and evidence gathering by the . Internal German suspicions may have been compounded by Schmidt's brother, , a general whose correspondence was later scrutinized, revealing indirect ties to sensitive information. However, the decisive catalyst remained Lemoine's betrayal, as no independent counterespionage leads—such as intercepted communications or anomalies—appear to have singled out Schmidt prior to the confession. This episode underscored vulnerabilities in Nazi security, where personal networks rather than systemic checks exposed long-standing moles.

Arrest and Interrogation

Hans-Thilo Schmidt's arrest stemmed from the detention of his primary French handler, Rodolphe Lemoine (alias Rex), who had been operating under German cover but was captured by authorities in occupied during early 1943. Under interrogation, Lemoine confessed and provided details implicating Schmidt as the source of leaked German military secrets, including Enigma-related materials. The arrested Schmidt on 1 April 1943 in , where he held a position in the Research Office of the Reich Air Ministry. Confronted with Lemoine's testimony and from security lapses in cipher operations, Schmidt faced intense questioning typical of procedures, which frequently employed physical coercion to extract admissions. During interrogation, Schmidt initially maintained denials but ultimately acknowledged his role in passing intelligence to French services from 1931 onward, though he minimized the extent of damage to German security. The process revealed the full scope of his activities, including deliveries of Enigma wiring diagrams and procedural manuals, confirming long-standing suspicions within Nazi intelligence circles.

Execution and Immediate Aftermath

Schmidt was arrested by the on April 1, 1943, after his long-time French handler, Rodolphe Lemoine (operating under the alias "Rex"), was captured and confessed to his espionage activities under interrogation, revealing Schmidt's identity as the source codenamed Asché. During subsequent custody in , Schmidt faced intense questioning regarding his betrayal of German military secrets, including details on the Enigma cipher machine provided to French intelligence in the 1930s. He died on September 19, 1943, at age 55; the cause remains disputed, with evidence pointing to either or extrajudicial execution by the regime, as no formal public trial records have surfaced. His daughter, , was called to the prison to identify his body shortly after the date of death. The immediate aftermath included scrutiny of Schmidt's family ties; his brother, General , commander of the Second Panzer Army on the Eastern Front, was relieved of duty in late 1943 due to association with the traitor, though investigations cleared him of direct involvement and he avoided execution. Lemoine, who had betrayed Schmidt, survived the war in custody but provided no further actionable intelligence to the Germans on Allied cryptanalytic efforts.

Contributions to Allied Intelligence Efforts

Transfer of Information to Poland and Britain

In December 1932, French military intelligence officer Gustave Bertrand shared key Enigma-related documents obtained from Schmidt with 's Cipher Bureau (Biuro Szyfrów), including an Enigma operating procedures manual from the late 1920s, rotor wiring diagrams, and daily message keys for September and October 1932. These materials, which Schmidt had procured through his access to the German Cipher Office via his brother Rudolf, a in the signals corps, enabled Polish cryptologists , Jerzy Różycki, and to reconstruct the Enigma's internal wiring—information absent from the outdated manual—and develop mathematical methods to exploit the provided keys for decrypting German traffic by late 1932. The Polish team's success relied directly on Schmidt's disclosures, as the daily keys revealed patterns in German operators' choices, allowing Rejewski to create the cyclometer device for efficient and produce daily decrypts of Enigma messages by January 1933. Schmidt's thus bridged French acquisition to Polish breakthroughs, with the Cipher Bureau decrypting an estimated 75% of Enigma traffic until modifications in reduced efficacy, prompting further innovations like . Schmidt's information reached Britain indirectly through Polish channels and limited direct contacts facilitated by French intermediaries. In July 1939, as war loomed, the Poles demonstrated Enigma replicas and shared their cryptanalytic techniques with British codebreakers at a meeting in Warsaw's Pyry forest, incorporating foundational insights derived from Schmidt's 1931–1932 leaks; this handover included two reconstructed Enigma machines gifted to the British. French intelligence, per accounts from counterespionage chief Paul Paillole, also brokered Schmidt's meetings with British officers in during the late , conveying warnings of German military preparations and additional cipher materials beyond Enigma, though these yielded less immediate cryptanalytic gains than the Polish relay. This multi-lateral transfer amplified Schmidt's espionage impact, seeding Allied Enigma efforts at .

Role in Early Enigma Cryptanalysis

Schmidt's provision of Enigma-related documents and settings to French in the early proved pivotal for the initial mathematical breakthroughs in the machine. Beginning in 1931, he supplied the French with the Enigma operating manual and detailed usage instructions, which described the machine's procedures but omitted internal rotor wirings. In mid-1932, Schmidt further delivered two pages of daily key settings, including plaintext-ciphertext pairs for messages enciphered on specific dates in and 1932, along with associated plugboard configurations. These materials offered concrete examples of Enigma's output, enabling cryptanalysts to reverse-engineer its permutations rather than relying solely on intercepted traffic. The French military cipher section, lacking the expertise to exploit this intelligence, forwarded the documents to Polish collaborators on December 8, 1932. , a young mathematician recruited by the Polish Bureau (Biuro Szyfrów), immediately applied the provided keys to model Enigma's encryption as a series of characteristic permutations. By assuming the third rotor's wiring mirrored earlier commercial Enigma models and using the known plaintext-ciphertext mappings from Schmidt's keys, Rejewski constructed and solved systems of equations that revealed the military rotors' internal wirings. This deduction, completed by December 15, 1932, marked the first recovery of an Enigma key and permitted decryption of subsequent messages. Building on this foundation, Rejewski and colleagues and Jerzy Różycki developed semi-automatic tools, including the cyclometer in 1934, to detect daily keys from message characteristics without needing further leaks. Schmidt's thus bridged the gap between theoretical understanding and practical , sustaining Polish breaks of Enigma traffic until the machine's 1938 upgrades introduced additional rotors and altered procedures, which overwhelmed their manual methods. Historians assess that absent these early disclosures, Allied codebreaking efforts at would have faced years of additional delay in achieving reliable decrypts.

Assessments and Legacy

Evaluation of Espionage Impact

Schmidt's provision of Enigma wirings, plugboard connections, and daily keys for September to December 1932 enabled Polish cryptanalysts, particularly , to reconstruct the machine's internal mechanisms and develop the bomba electromechanical device for decrypting and messages by late 1932. This breakthrough allowed to read substantial German traffic until 1938, when Enigma modifications outpaced their capabilities, providing a three-year head start absent in other nations' efforts. Without Schmidt's materials, later assessed that Polish success would have been delayed significantly, as initial mathematical attacks lacked the concrete data needed to verify permutations. The intelligence chain continued when Polish cryptographers shared their findings, including Schmidt-derived insights, with British codebreakers at Pyry in July 1939, directly informing the design of Turing's machine at . This facilitated the production of Ultra decrypts, which British officials estimated shortened the war by two to four years by yielding actionable intelligence on dispositions, supply convoys, and operations. Schmidt's leaks thus formed a causal foundation for Allied cryptanalytic dominance, amplifying the strategic value of Enigma breaks in pivotal campaigns like the , where timely decrypts enabled convoy rerouting and reduced merchant shipping losses from over 7 million tons in 1941-1942 to under 1 million by 1944. Historians regard Schmidt's espionage as pivotal, with assessments crediting it for initiating the collaborative Allied effort that decrypted millions of German messages, potentially averting greater casualties and altering outcomes in and preparations. French intelligence's initial acquisition and transmission to , despite internal delays in exploitation, underscored the materials' high fidelity and timeliness, as verified by post-war analyses confirming the accuracy of provided keys against intercepted traffic. Overall, the espionage's impact lay in bridging theoretical with empirical validation, enabling scalable machine-assisted decryption that outmatched German assumptions of Enigma's security.

Criticisms and Alternative Viewpoints

Some accounts emphasize limitations in Schmidt's contributions, noting that the Enigma documents he supplied in December 1931—including operating instructions and monthly key settings for January and February 1932—proved insufficient for French cryptanalysts to achieve routine breaks, despite their access to the raw materials. French military cryptanalysis efforts faltered due to inadequate mathematical expertise and failure to prioritize machine-based solutions, even after receiving Schmidt's intelligence, which contrasted with the Poles' success in reconstructing rotor wirings upon indirect receipt of the same documents in July 1932. This highlights a viewpoint that espionage alone could not substitute for advanced cryptanalytic methods, as Enigma's evolving configurations—such as the addition of a fourth rotor by 1938 and expanded plugboard settings—rendered earlier keys obsolete for wartime traffic. Alternative perspectives question the necessity of Schmidt's materials for the Polish breakthrough, with some suggesting Marian Rejewski's permutation-based for Enigma cycles might have been developed independently, drawing from intercepted messages of a commercial Enigma variant rather than relying heavily on the spy's static documents. Schmidt's motivations have also drawn scrutiny, as he initiated contact with French primarily for —receiving payments equivalent to over 100,000 francs by the mid-1930s—rather than ideological resistance to Germany's rearmament, a factor that some histories frame as pragmatic amid personal debts from a lavish . Debates persist on the broader Allied impact, with British accounts like those from underscoring that wartime Ultra successes stemmed more from Bletchley Park's innovations—such as Turing's and —than from Schmidt's pre-1938 disclosures, which provided a starting point but required substantial independent adaptation to handle daily key variations and indicator flaws exploited later. These views counter narratives overstating Schmidt's role by privileging empirical cryptanalytic achievements over the spy's foundational leaks, while acknowledging French delays in sharing his intelligence with allies until the 1939 meeting exacerbated missed opportunities pre-invasion.

Depictions in Historical Accounts

Historical accounts portray Hans-Thilo Schmidt primarily as a financially motivated traitor within Germany's cipher apparatus, whose leaks of details provided the initial impetus for Allied codebreaking efforts, though often contrasted with the technical ingenuity of Polish cryptanalysts. In Paul Paillole's The Spy in Hitler's Inner Circle (originally published in French as Notre espion chez Hitler), Schmidt is depicted as "Asché" or "H.E.", a Foreign Office clerk who from December 1931 onward delivered operating manuals, daily key settings, and strategic plans—including those accessed via his brother, General —to French intelligence officers Rodolphe Lemoine and Paul Paillole himself. Paillole, leveraging his role as counterespionage chief in the , frames these disclosures as enabling the relay of intelligence to Poland's Biuro Szyfrów and Britain's Government Code and Cypher School, ultimately aiding decrypts that influenced outcomes like the in 1940 and the Normandy invasion in 1944. This insider perspective from Paillole, however, invites scrutiny for potentially inflating French contributions relative to Schmidt's raw material, as the Deuxième Bureau's cryptanalytic follow-through lagged behind Polish advancements despite receiving the Enigma user manual on September 25, 1931, and monthly settings for September and October 1932. In contrast, Dermot Turing's X, Y & Z: The Real Story of How Enigma Was Broken (2018) characterizes Schmidt as a "classic amoral spy" driven by monetary gain and personal indulgences, lacking any anti-Nazi conviction despite his membership (No. 738,736) from December 1, 1931; Turing stresses that Schmidt's documents supplied wiring permutations and procedural insights but required Marian Rejewski's permutation-based methods to yield the first breaks by December 1932. Gustave Bertrand's Enigma (1973), drawing from French archives declassified after Schmidt's identity surfaced publicly in 1974, depicts him as an opportunistic "weakling" (per German investigator Walther Seifert's term) whose betrayals stemmed from business failures and habits, such as seducing domestic staff, yet whose October 1931 overtures yielded recoveries that Poles replicated commercially for . Bertrand's account, informed by direct handling of Schmidt's outputs, underscores the spy's longevity—active until his September 19, 1943, execution—while noting German countermeasures like Enigma modifications post-1937 diminished his later utility. Later analyses, including Jean-François Bouchard's The German Spy and the Codebreakers (2016), fill archival gaps by detailing Schmidt's handovers, such as rotor wirings and plugboard indicators, portraying him less as a master agent than a bureaucratic insider exploiting lax for profit, with his amplifying but not originating the mathematical assault on Enigma. These works collectively evaluate Schmidt's legacy as foundational yet auxiliary, crediting human betrayal for the "head start" that empirical then exploited, without which British Ultra successes at might have been deferred by years.

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