T-shirt detail

[cme@ellisun.sw.stratus.com (Carl Ellison)]

Sorry for distracting people with my T-shirt suggestion, but the more
I think about it, the more I like "celebrating 4000 years..." -- possibly
on the back.

On the front, I'd have 4 boxes (or regions set apart):

		LEB KAMAI


				y_i = x_i + k_{(i mod m)}


		y_i = x_i (+) k_i


				y = x^e mod N

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1. LEB KAMAI, in Hebrew characters from the Bible -- cf., Kahn's "The
Codebreakers", pp. 77-78 -- atbash cipher, stronger than Caesar's and
predating him by more than a month :-)

2. polyalphabetic substitution -- stronger than nomenclators (based on when
attacks were known to exist) but ignored by gov't users for 100s of years

3. Vernam's tape -- theoretically unbreakable -- in the hands of citizens
from about 1920 {the (+) is a circled "+" -- meaning XOR}

4. RSA -- 1978

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It might be interesting to date the four boxes.  Anyone have a date for
the LEB KAMAI?

 - Carl