Re: Reverse caesar cipher

From: John A. Malley (102667.2235_at_compuserve.com)
Date: 11/30/04 

Date: Mon, 29 Nov 2004 22:00:14 -0800

Joe Peschel wrote:
> "John A. Malley" <102667.2235@compuserve.com> wrote in
> news:41AAB011.3050102@compuserve.com:
>
>
>>KelvinLJ27 wrote:
>>
>>>Been trying to decode this, " YKNAN RAN EDV YKJELZ RQDXY FRYK J MJEO
>>>JEYNANZYJEL" all night and can't get it. Help Please!!!
>>
>>It is ciphertext from a reverse Caesar cipher.
>
>
> I wouldn't call it that.

You're right, I think it's technically a Beaufort cipher, using the
formula c = (k - p) mod 26, where k = keytext, c = ciphertext and p =
plaintext all converted to a number in [0-25] representing [A-Z]. There
is a single fixed k value for all plaintext characters.

>>I cracked it with a
>>probable word attack
>
>
> Interesting.

Yes! Just look at "J." How many English words could it be? :-) That's
the easiest way in.

John A. Malley
102667.2235@compuserve.com 

-- 
Their blood is the ink for the new maps...

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