In message <[EMAIL PROTECTED]>, Greg Rose writes
:
>At 01:30 AM 10/2/2002 -0400, John S. Denker wrote:
>>"R. A. Hettinga" wrote:
>>...
>> > "the first computer to crack enigma was optical"
>>1) Bletchley Park used optical sensors, which were (and
>>still are) the best way to read paper tape at high speed.
>>You can read about it in the standard accounts, e.g.
>> http://www.picotech.com/applications/colossus.html
>
>But Colossus was not for Enigma. The bombes used for Enigma were
>electro-mechanical. I'm not aware of any application of optical techniques
>to Enigma, unless they were done in the US and are still classified. And
>clearly, the first bulk breaks of Enigma were done by the bombes, so I
>guess it depends whether you count bombes as computers or not, whether this
>statement has any credibility at all.
>
If memory serves (my references are at home), the Bletchley Park crew
used holes punch in large grids. They'd overlap many sheets and see
where the light made it through; that would be a good key (or candidate
key).
I don't know if you'd call that a "computer", but it was an interesting
optical device. I'm sure there have been many later applications of
similar principles -- see Shamir's TWINKLE, for example, which relied on
detecting aggregate brightness over many LEDs.
--Steve Bellovin, http://www.research.att.com/~smb (me)
http://www.wilyhacker.com ("Firewalls" book)
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