Turing and origins of UKUSA

Anish Mohammed anish.mohammed at gmail.com
Sun Jun 24 21:38:49 BST 2012

Looks like we have been good at being "economic" with truth :)

On Sun, Jun 24, 2012 at 7:50 PM, Caspar Bowden (travelling)
<tharg at gmx.net>wrote:

>  On Turing Day +1 thought ukcrypto might enjoy this....
> 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 NSA
> published <http://www.nsa.gov/public_info/declass/ukusa.shtml>significantly more (and different) material than released
> in UK <http://www.nationalarchives.gov.uk/ukusa/>, and I was intrigued by
> several aspects of the US "early papers 1940-1944"<http://www.nsa.gov/public_info/_files/ukusa/early_papers_1940-1944.pdf>
> 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 SIGSALY<http://www.nsa.gov/about/cryptologic_heritage/center_crypt_history/publications/sigsaly_story.shtml>).
> 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)
> 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.
> Previous primary sources include Turing's initial report<http://www.turing.org.uk/sources/washington.html>(Nov 28th)  of his US trip (released in 2004), which opened
> 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
> ..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
> . T
> 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.
> 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)
> 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.
> There are several gems in the documents but favourite so far is :
> "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)
> CB

Anish Mohammed
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