FBI Investigated Historian David Kahn Before NSA Honors

David Kahn, a historian known for his work on cryptography and espionage, received multiple honors from the National Security Agency (NSA) throughout his career, including a scholar-in-residence title and induction into the NSA Hall of Fame. However, prior to these accolades, Kahn was the subject of an FBI investigation that began in the early 1950s. The FBI's interest in Kahn stemmed from his correspondence with Frederic C. Flindt, during which Kahn mailed restricted Army documents to Flindt, who was also a cryptography enthusiast.

In 1953, the U.S. Army Counterintelligence Corps alerted the FBI about Kahn's activities, leading to a stakeout at a post office where Flindt picked up a package from Kahn containing government cryptography manuals. Flindt cooperated with the FBI, revealing that he and Kahn were building an unauthorized archive of cryptographic materials. Kahn, then a 23-year-old Army reservist, explained that he considered the manuals collector's items and did not see them as classified.

Despite Kahn's defense, the FBI confiscated the materials and initiated an investigation that reached FBI Director J. Edgar Hoover. Kahn's father, a lawyer, later contacted the FBI, expressing concern over his son's actions and asserting that Kahn was not a security risk. The momentum for prosecution waned, and by early 1954, Kahn was able to retrieve his confiscated materials.

Kahn's relationship with the FBI evolved over the years. While working as a journalist, he received information from the FBI about espionage cases, including that of Soviet spy Rudolf Abel. However, the FBI remained cautious about Kahn's activities, warning that his book on cryptology might contain sensitive information. Despite this, Kahn's persistence and passion for cryptography ultimately led to a change in perception.

The NSA later recognized Kahn's contributions to the field, stating that many of its staff were inspired to pursue cryptology because of his writings. Kahn's legacy transformed from that of a potential security threat to a respected educator on the importance of cryptology in international peace and security. His journey reflects a remarkable shift in the government's view of his work and character, showcasing how curiosity and determination can lead to significant achievements.