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<p class="MsoNormal"><span style="font-size:11.0pt">I have a link to a google drive provided by the US Cryptological Museum that contains intelligence reports from back in that time. There are a lot of documents, and nothing about US non-intel info, but it
shows what the US intercepted and decoded at the time in a couple of documents. There are also other interesting documents about other stuff, the list can easily steal large amounts of time from the curious.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><a href="https://drive.google.com/drive/folders/1jQ64F-fsqBCZDV6_ErtQ4zCiVqw_VXWy">https://drive.google.com/drive/folders/1jQ64F-fsqBCZDV6_ErtQ4zCiVqw_VXWy</a><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt">Darren Hersey<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt">703-621-4016</span><span style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="font-size:12.0pt;color:black">From:
</span></b><span style="font-size:12.0pt;color:black">cryptography <cryptography-bounces+dhersey=akamai.com@metzdowd.com> on behalf of Steven M. Bellovin <smb@cs.columbia.edu><br>
<b>Date: </b>Thursday, June 19, 2025 at 10:12</span><span style="font-size:12.0pt;font-family:"Arial",sans-serif;color:black"> </span><span style="font-size:12.0pt;color:black">PM<br>
<b>To: </b>John Levine <johnl@iecc.com><br>
<b>Cc: </b>cryptography@metzdowd.com <cryptography@metzdowd.com>, hbaker1@pipeline.com <hbaker1@pipeline.com><br>
<b>Subject: </b>Re: [Cryptography] Pearl Harbor<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt">!-------------------------------------------------------------------|<br>
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You may want to look at page number 37 of <a href="https://urldefense.com/v3/__https:/www.nsa.gov/portals/75/documents/news-features/declassified-documents/friedman-documents/pearl-harbor/FOLDER_494/41782679082173.pdf__;!!GjvTz_vk!RztMFsWRdXqsP-5qx59xThYr7Ej4AoWkZHGl52qyJON51IiZt_VdNuZFEwvgQITwbWDW6DETa9uRDwg$">
https://urldefense.com/v3/__https://www.nsa.gov/portals/75/documents/news-features/declassified-documents/friedman-documents/pearl-harbor/FOLDER_494/41782679082173.pdf__;!!GjvTz_vk!RztMFsWRdXqsP-5qx59xThYr7Ej4AoWkZHGl52qyJON51IiZt_VdNuZFEwvgQITwbWDW6DETa9uRDwg$</a>
— it's a declassified document from the Friedman Collection, released by the NSA about 10 years ago. Another document from the Friedman collection, which I can't find at the moment, noted that in May 1941 the US actually wargamed a Japanese carrier-based attack
on Pearl Harbor—but forgot about it. Add to that a non-trivial amount of anti-Japanese racism, and you had the makings of a disaster.<br>
<br>
From everything I've read, the US had known for quite some time that war was coming, with the tip-off that war was imminent just before Pearl Harbor, but they didn't know just where Japan would strike—attacks much closer to home and to the south were seen as
far more likely. Japan had excellent operational security and didn't leak anything. (I once asked an expert why the crack of the Purple machine, used for Japanese diplomatic communications, didn't give any clues—the Allies learned a lot from communications
between Tokyo and Berlin (https://urldefense.com/v3/__https://en.wikipedia.org/wiki/Hiroshi_**Ashima__;xYw!!GjvTz_vk!RztMFsWRdXqsP-5qx59xThYr7Ej4AoWkZHGl52qyJON51IiZt_VdNuZFEwvgQITwbWDW6DEThk_i1PY$ ). The answer, I was told, was that the Japanese ambassador
had been a general in the Japanese Army, whereas the strike on Pearl Harbor was a Navy operation, and interservice rivalry meant that he and the Army were never told.)<br>
<br>
--Steve Bellovin, <a href="https://urldefense.com/v3/__https:/www.cs.columbia.edu/*smb__;fg!!GjvTz_vk!RztMFsWRdXqsP-5qx59xThYr7Ej4AoWkZHGl52qyJON51IiZt_VdNuZFEwvgQITwbWDW6DETw3Y-6Tc$">
https://urldefense.com/v3/__https://www.cs.columbia.edu/*smb__;fg!!GjvTz_vk!RztMFsWRdXqsP-5qx59xThYr7Ej4AoWkZHGl52qyJON51IiZt_VdNuZFEwvgQITwbWDW6DETw3Y-6Tc$</a>
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