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On Turing Day +1 thought ukcrypto might enjoy this....<br>
<br>
As list members no doubt recall al couple of years ago the UK
National Archives and the NSA simultaneously published a lot of
material on the UKUSA intelligence sharing agreements originating in
WW2. However the <a
href="http://www.nsa.gov/public_info/declass/ukusa.shtml">NSA
published</a> significantly more (and different) material than <a
href="http://www.nationalarchives.gov.uk/ukusa/">released in UK</a>,
and I was intrigued by several aspects of the US <a
href="http://www.nsa.gov/public_info/_files/ukusa/early_papers_1940-1944.pdf">"early
papers 1940-1944"</a><br>
<br>
Turing visited the US in November 1942, mainly to inspect US
production of bombes and have a shufti at US methods, but also to
look at work in Bell Laboratories on a new speech scrambler (likely
what became <a
href="http://www.nsa.gov/about/cryptologic_heritage/center_crypt_history/publications/sigsaly_story.shtml">SIGSALY</a>).
However he was refused permission, and the "early papers" document
the US Army side of an escalating row which lasted until a prototype
of UKUSA was concluded in May 1943 (long before BRUSA in 1946)<br>
<br>
The row was about the fact the US had become suspicious the UK was
holding back info on the Lorenz machine cipher (Tunny), although the
US had briefed the UK on the breaking of the Japanese PURPLE; also
that the UK wanted to keep control of Enigma exploitation because of
worries about security (reasonable because the US wouldn't tell them
the technology the US wanted to use to protect the dissemination of
decrypts); and that also the US Navy had got full access to UK
decrypts of German U-Boat Enigma but such agreements hadn't been
reached with the US Army for the European of African theaters.<br>
<br>
Previous primary sources include <a
href="http://www.turing.org.uk/sources/washington.html">Turing's
initial report</a> (Nov 28th) of his US trip (released in 2004),
which opened<br>
<br>
<tt>I reached New York on Friday November 12th. I was all but kept
on Ellis Island by the Immigration Authorities who were very
snooty about my carrying no orders and no evidence to connect me
with the F.O. They considered my official's passport insufficient
in itself. They asked me very minute details about where I was to
report etc. I think it might have been better from a security
point of view if I had been provided with some kind of document of
the kind they wanted, to say nothing of the possibility that I
might have been held until Stevens or somebody identified me<br>
<br>
</tt>..and continues with understated humour about the US approach
to the work. Turing is optimistic in the report that "all now seems
to be well" re: problem with visiting Bell Labs, but the "early
papers" show that he did not get permission until Jan 9th. His UK
minder Maj.Stevens in a covering note supports Turing skepticism and
adds<br>
. T<br>
<tt>They (the US) are jokingly credited with wanting to take all
traffic that comes in and subject it immediately to every known
process, regardless that some of it may be P/L or in a cipher
which they hold.
</tt><br>
<br>
Amazingly Turing had not had instructions about whether he was
allowed to brief the US on Tunny (i.e. that by this time Tutte had
reconstructed the Lorenz machine purely with manual analysis), and
evidently had to keep this from the formidable US cryptographer
Friedman (that must be one of the all time cagey conversations)<br>
<br>
What I haven't seen written up in any historical work since 2010 is
that relations became so bad in early 1943 that the UK were
contemplating cutting off the US from Continental Enigma (at least
the US Army thought so, and advised to call what they assumed was a
UK bluff). The corresponding documents on the UK side weren't
released. The US Army resented the fact they got trumped "in the
Turing case" and that GCCS had access to Churchill "and therefore to
F.D.R" which they evidently lacked.<br>
<br>
There are several gems in the documents but favourite so far is :<br>
<br>
"They (the UK) set forth the claim that in connection with this
whole subject of secret communications equipment, either voice
scrambling, cipher machines or anything of a similar nature, the
specialists who are experts in cryptanalysis or descrambling, should
be in on the initial development of the equipment. In that way these
experts (according to Tiltman et al) can point out weaknesses in
design which could be corrected in the development period. They
claim that hundreds of man hours could be saved if this procedure
were followed rather than to have a machine developed in one
laboratory and then to give to another laboratory the job of
breaking down its traffic. In my opinion, this is merely another
attempt to gain access to technical information on our cipher
machines and ultra secret scrambling devices and is not a plausible
argument" (Dec 17 1942)<br>
<br>
CB<br>
<br>
<br>
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