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Laurance Safford

Laurance Safford is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Laurance Safford rather than just read about it. In short: Captain, U.S.N. Laurance Frye Safford (October 22, 1893 – May 15, 1973) was a U.S.

Laurance Safford — main illustration
Laurance Safford — illustration

Key takeaways

  • Laurance Safford belongs to computer science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Laurance Safford to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Laurance Safford from memory before moving on to harder problems.

Reference excerpt

Captain, U.S.N. Laurance Frye Safford (October 22, 1893 – May 15, 1973) was a U.S. Navy cryptologist. He established the Naval cryptologic organization after World War I, and headed the effort more or less constantly until shortly after the Japanese attack on Pearl Harbor. His identification with the Naval effort was so close that he was the Friedman of the Navy.

Biography Safford was born in 1893 in Somerville, Massachusetts. He secured an appointment to Annapolis, and graduated fifteenth in the class of 1916. In January 1924 he was called from command of a minesweeper off the China coast to head the "research desk" of the Code and Signal Section within the Office of Naval Communications. In the beginning his sole task was to exploit a Japanese naval codebook that had been filched from the Japanese consulate in New York City. To do this he had four civilian clerical employees. Safford promoted the effort throughout the Navy, attracting Agnes Meyer Driscoll, Joseph Rochefort, Joseph Wenger, and others who were to lead the business through World War II and into the postwar period. He was the first to begin organizing the worldwide Naval collection and direction finding effort, so that when the United States entered World War II it already had a system of intercept stations. Safford himself was wrenched out of the job in 1926, returning in 1929. He remained with the effort except for another sea tour from 1932 to 1936. Meanwhile, the effort that he headed broke Japanese naval codes, and began mechanizing its operations with the addition of IBM equipment. Safford himself was directly involved with building cryptographic machines, and collaborated with the Army's Frank Rowlett in the invention of the Sigaba, a cipher machine not known to be broken by any country during World War II. Safford promoted collaboration with the Army on several fronts and was mostly responsible for the Navy entry into a joint effort with the Army on the Japanese diplomatic systems. He recognized the signs of war that appeared in the diplomatic traffic, and he tried to get a warning message to Pearl Harbor several days before the attack but Director of Naval Communications Admiral Noyes rebuffed him. Organizationally, he promoted a decentralized system with Naval COMINT sections in Washington, Hawaii, and Manila. He gave the chief Japanese naval code problem to the organization in Hawaii, and named Joseph Rochefort to head the effort. He also gave Rochefort a blank check to obtain the very best Navy cryptanalysts. That paid off in the spring of 1942, when Rochefort's team, though unable to break JN-25, the main Japanese naval operational code, was able to deduce important information from it, largely through traffic analysis, in time to help win the Battle of Midway. Rochefort's team was also able to trick the Japanese Navy into sending a message that revealed that it was Midway that was the focus of the attack, not the Aleutians, as Washington cryptanalysts maintained. While many historians have insisted that Rochefort's team failed to crack the JN-25B naval code, the declassified intercepts refute the notion. In August 1970, Safford reaffirmed his views: "By Dec.1/41, we had the code solved to a readable extent."(Wilford, Decoding Pearl Harbor: USN Cryptanalysis and the Challenge of JN-25B in 1941). But this is sharply disputed in Tower of Skulls by Richard B. Frank, citing a report written during the war that says that no messages in JN-25 were read in 1941. He was promoted to captain shortly after the United States entered the war, on January 1, 1942. Power struggles with the Navy soon led to Safford's ouster in February 1942, with John R. Redman and Joseph Wenger heading sections of OP-20-G. Safford was sidelined for the remainder of the war, as ultimately was Rochefort. He retired from active duty in 1953 and died in May 1973.

Amelia Earhart About 1970 he began a lengthy analysis of the 1937 flight across the Pacific on which Amelia Earhart disappeared, and after establishing the intricate radio transmission documentation he concluded "poor planning, worse execution". A book was subsequently published: Earhart's Flight into Yesterday: The Facts Without the Fiction by Laurance F. Safford with Cameron A. Warren & Robert R. Payne (c2003, Paladwr Press, McLean VA USA) ISBN 1-888962-20-8

Works Earhart's Flight into Yesterday: The Facts Without the Fiction (Paladwr Press, 2002) ISBN 1-888962-20-8

References

External links Laurance Safford in NSA Hall of Fame

Illustrations

Laurance Safford illustration

Worked examples

Example 1 — a first encounter with Laurance Safford

Start with the simplest possible case. Write down what Laurance Safford claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Laurance Safford before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Laurance Safford ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Laurance Safford

In research
Laurance Safford appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Laurance Safford in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Laurance Safford is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1893 births, 1973 deaths, 20th-century cryptographers, so understanding it makes those chapters shorter.
In everyday life
Look for Laurance Safford outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Laurance Safford in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Laurance Safford means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Laurance Safford out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Laurance Safford in simple terms?

Captain, U.S.N. Laurance Frye Safford (October 22, 1893 – May 15, 1973) was a U.S.

Why does Laurance Safford matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Laurance Safford?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Laurance Safford.

Tags

  • 1893 births
  • 1973 deaths
  • 20th-century cryptographers
  • American cryptographers
  • Intelligence analysts
  • People from Somerville, Massachusetts
  • Recipients of the Legion of Merit
  • United States Naval Academy alumni
  • United States Navy officers
  • United States Navy personnel of World War I
  • United States Navy personnel of World War II

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