Herbert Yardley and a Redacted Lineage of American Codebreaking
By Vera Kessler ·
A three-volume history of American cryptography remained secret for decades, and specific details of the pre-1940 era remain blacked out today.
The risk of a broken code is the risk of a lost war, or a betrayed diplomat. When the state decides which parts of its cryptologic history to preserve and which to redact, it is deciding who owns the truth about how we listen to the world.
I am working from the archival scope-and-content description of these files, a catalogue that maps the ghost of a three-volume study. This record describes a "redacted copy of a three-volume study prepared by the Army Security Agency" which attempts to chart the "story of the development of cryptography in the United States from 1776 to 1939" (Historical Background Records of the Signals Security Agency). The study was maintained by the National Security Agency/Central Security Service, the DoD combat support agency established in 1972 to integrate NSA operations with military signals intelligence.
The 1939 Firewall
The study's chronological boundary is not a coincidence; it is a border. The record establishes that the volumes cover everything from the Revolutionary period to the "establishment of the Army Signal Intelligence Service" (Historical Background Records of the Signals Security Agency). The Army Security Agency—the Army's signals intelligence branch from 1945 to 1977—was the author of this history. The public record shows that the Army Security Agency's resources were eventually absorbed by the NSA, creating a direct line of inheritance from the analysts of the 1940s to the surveillance state of today.
The desk's reading is that the 1939 cutoff is a deliberate firewall designed to separate institutional genealogy from operational methodology. By ending the history on the eve of the United States' full entry into World War II, the agency isolates the "story" of its birth from the actual mechanics of its expansion. The 1940s marked the transition of cryptanalysis from a periodic military tool used during crises to a permanent state apparatus. If the study had continued into the 1940s and 50s, it would have had to document the shift from breaking codes to managing a global vacuum of information. By stopping at 1939, the agency preserves a narrative of evolution while burying the evidence of a mutation.
Yardley and the Utility of Failure
Central to the record is the inclusion of "Herbert Yardley's 'American Black Chamber' organization and its accomplishments" (Historical Background Records of the Signals Security Agency). Yardley was the cryptologist who founded and led the Black Chamber, the first peacetime cryptanalytic organization of the US government, which operated from 1917 to 1929. The public record establishes that Yardley’s team broke Japanese diplomatic codes, providing US negotiators with an asymmetrical advantage during the 1921–1922 Washington Naval Conference.
There is a sharp irony in the agency's desire to document Yardley. The Black Chamber was not shut down because its mission was complete, but because the government grew wary of its independence. Yardley eventually became the ultimate whistleblower, publishing the secrets of the Black Chamber in his own books and effectively burning the house down. He turned the state's most guarded secrets into a public commodity.
The pattern suggests that the institutional focus on Yardley in this study is an attempt to retroactively absorb a public intelligence failure and a whistleblower's narrative into an official lineage of success. By framing Yardley's Black Chamber as a "forerunner" to the NSA, the agency transforms a cautionary tale of betrayal into a foundational chapter of institutional growth. The agency is not honoring Yardley; it is annexing him. It claims the "accomplishments" listed in the record while erasing the defiance that defined Yardley's later life.
A Genealogy of Vigilance
The record shows the study reaches back further than the 20th century, documenting "American and British systems in the Revolutionary period" and the "Federal, Confederate, and Diplomatic systems in the Civil War" (Historical Background Records of the Signals Security Agency). These records were originally housed in the War Department—the pre-1947 defense ministry—specifically within the Office of the Chief Signal Officer, which managed the Army Signal Intelligence Service. This SIS was the Army codebreaking division founded in 1930 to compile codes, eventually evolving through two name changes into the Army Security Agency.
The line between the Revolutionary War and the Cold War is drawn here to create a sense of inevitability. If the state can show that it has been breaking codes since 1776, then the existence of a massive, permanent signals intelligence agency is not a radical expansion of power, but the fulfillment of a patriotic destiny. The desk's reading is that this document functions as a foundational myth. By linking the NSA's origins to the struggle for independence and the preservation of the Union, the agency frames its surveillance capabilities as an essential attribute of American sovereignty rather than a product of Cold War paranoia.
The Operational Gap
The most telling part of the record is not what it includes, but what it excludes. The study ends in 1939. However, related series in the same archive skip forward violently to "Modification Tables of Organization and Equipment (MTOEs)" detailing the organizational structure of U.S. military organizations in Vietnam. This leaves a cavernous gap between 1940 and the 1960s—the exact period when the US built the infrastructure of modern signals intelligence.
If the shape of this file is what it appears to be, the records of the agency's most transformative period are categorized as operational rather than historical. The agency is happy to provide a "history" of the 18th century, but it treats the mid-20th century as a live circuit. The fact that the 1776–1939 study remains a "redacted copy" is the final piece of the puzzle. There is no logical reason for a history of the Revolutionary War or the Civil War to require redactions in the present day, unless those redactions are not about people or dates, but about logic.
The pattern suggests that the specific logic or vulnerabilities of early 20th-century systems remain conceptually relevant to current secure communications. The gaps and the blackouts are not protecting the ghosts of the 1930s; they are protecting the blueprints of the present. The agency has released a sanitized genealogy to prove its legitimacy, while keeping the operational bridge from 1940 to the present hidden. The cost of this curation is a public record that views the NSA as an inevitable evolution of the American spirit, while the actual mechanics of its power remain an open secret, carefully redacted.