$20 bounty for errors in _Disappearing Cryptography_

2008-06-03 Thread Peter Wayner


I'm working on the third edition of _Disappearing Cryptography_ right  
now. If anyone knows of any technical errors in the second edition,  
I'm willing to pay $20 for the first person to report each technical  
error.


The bounty can't apply to grammatical errors because of the  
complexity of the language. I reserve the right to (1) decide on  
whether something is a legitimate technical error and (2) give out  
more than one award if several people send in the same bug report and  
seem to be genuinely independent. The limit is just meant to stop  
people from minting money.


Thanks,


-Peter Wayner
[EMAIL PROTECTED]

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Re: Simple inner transposition steganography

2003-09-18 Thread Peter Wayner
At 4:01 PM -0400 9/18/03, [EMAIL PROTECTED] wrote:
On Thu, 18 Sep 2003, edo wrote:

 Maybe it works as a very, very weak form of encryption, one which can
 be decrypted at a glance by humans but would evade the most simplistic
 computer recognition systems.  But stego it ain't.
Steganography is in the eye of the beholder.
Very nice line.

I have to agree. There are always two channels in steganography and 
its cousin watermarking. You want to make changes in one channel so 
the other channel isn't affected. In this case, a munged word doesn't 
affect the human reader but it can carry log_2(n!) bits where n=count 
of non-duplicate letters - 2. So we have two channels.

Now, I will admit that a large number of munged words will trigger 
something in the human, but it's entirely possible that three or four 
munged words on a page WON'T EVEN BE NOTICED. Believe me. I've proof 
read books a number of times and it's surprising how much gets 
through even the best copy editors.

Three or four words per page is also enough to insert more than a few 
bits of watermarking. A seven letter word can carry almost seven 
bits. So let's call it 6 bits. If you change four seven letter words 
on a page, you've 24 bits. Not bad.



-Peter

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