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PRODID:-//archive.cryptologicfoundation.org//NONSGML kigkonsult.se iCalcrea
 tor 2.30.10//
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UID:37533f74-a9bb-4137-bb62-d4351a79bf03
X-WR-CALDESC:31 October 1929: The Cipher Bureau ('Black Chamber') headed by
  Herbert O. Yardley closed. Read about the Black Chamber in an NSA article
 : via the link at the end of the page.\n\nAfter the organization disbanded
 \, Yardley caused a sensation in 1931 with the publication of his memoirs 
 of MI-8\, 'The American Black Chamber.' In this book\, Yardley revealed th
 e extent of U.S. cryptanalytic work in the 1920s. Surprisingly\, the wordi
 ng of the espionage laws at that time did not permit prosecution of Yardle
 y. (This situation was changed two years later with a new law imposing sti
 ff penalties for unauthorized revelations of cryptologic secrets.)  In a 1
 952 letter\, William Friedman\, a contemporary of Yardley\, suggested\, 'I
 n reading Yardley I recommend ingestion of liberal dozes of sodium chlorid
 e.' (i.e.\, Take it with more than a grain of salt.)\n\nYardley did some c
 ryptologic work for Canada and China during World War II\, but he was neve
 r again given a position of trust in the U.S. government.\n\nRead more abo
 ut Herbert O. Yardley in NSA's collection of Yardley-related articles.
X-WR-RELCALID:436c956c2b3b1a4517591a5e9bd53f2c
X-WR-TIMEZONE:America/New_York
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TZID:America/New_York
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TZNAME:EST
DTSTART:20251102T020000
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
RDATE:20261101T020000
RDATE:20271107T020000
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DTSTART:20260308T020000
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TZOFFSETTO:-0400
RDATE:20270314T020000
RDATE:20280312T020000
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BEGIN:VEVENT
UID:e0fd5cf2-956d-442b-a9c3-89bed1ad4b8b
DTSTAMP:20260424T142434Z
DESCRIPTION:31 October 1929: The Cipher Bureau ('Black Chamber') headed by 
 Herbert O. Yardley closed. Read about the Black Chamber in an NSA article:
  via the link at the end of the page.\n\nAfter the organization disbanded\
 , Yardley caused a sensation in 1931 with the publication of his memoirs o
 f MI-8\, 'The American Black Chamber.' In this book\, Yardley revealed the
  extent of U.S. cryptanalytic work in the 1920s. Surprisingly\, the wordin
 g of the espionage laws at that time did not permit prosecution of Yardley
 . (This situation was changed two years later with a new law imposing stif
 f penalties for unauthorized revelations of cryptologic secrets.)  In a 19
 52 letter\, William Friedman\, a contemporary of Yardley\, suggested\, 'In
  reading Yardley I recommend ingestion of liberal dozes of sodium chloride
 .' (i.e.\, Take it with more than a grain of salt.)\n\nYardley did some cr
 yptologic work for Canada and China during World War II\, but he was never
  again given a position of trust in the U.S. government.\n\nRead more abou
 t Herbert O. Yardley in NSA's collection of Yardley-related articles.
DTSTART;TZID=America/New_York:20261031T000000
DTEND;TZID=America/New_York:20261031T235900
LOCATION:
SUMMARY:1929: Cipher Bureau Closed.
END:VEVENT
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