CDR: Re: Re: Spam free secure email accounts.

[Bill Stewart]

At 06:07 PM 10/4/00 -0500, Jim Choate wrote:
>On Wed, 4 Oct 2000, Ray Dillinger wrote:
>> On Wed, 4 Oct 2000, Tom Vogt wrote:
>> > how do you find out whether or not a message is encrypted?
>>
>> Plaintext looks like plaintext.
>
> Yeah, if the only thing you right is simple English. 
> Most of the planet doesn't speak English and their plaintext 
> doesn't necessarily look like plaintext.  This is a xenophobic view.

8-bit-alphabet plaintext looks like plaintext.
It's easier to recognize popular languages - short bunches of 
letters separated by spaces.  Less popular languages that use
8-bit alphabets still have easily detected statistics that
are much different from uniformly-distributed cyphertext.

Languages with N-byte characters are much harder -
you have to decide whether to look at Unicode,
(2-byte's bad enough; variable-byte is worse),
otherwise you'll get totally hosed on your chi-squares.

Things that start with popular magic numbers like gif89 
also look like plaintext (though they may in fact be stego.)


				Thanks! 
					Bill
Bill Stewart, bill.stewart at pobox.com
PGP Fingerprint D454 E202 CBC8 40BF  3C85 B884 0ABE 4639