Subject: Re: New Documentation: Encrypted CDs/DVDs
To: NetBSD User's Discussion List <>
From: Steven M. Bellovin <>
List: netbsd-users
Date: 03/15/2005 14:39:07
In message <>, "Greg A. Woods" writes:
>[ On Sunday, March 13, 2005 at 13:30:18 (+0100), Florian Stoehr wrote: ]
>> Subject: Re: New Documentation: Encrypted CDs/DVDs
>> Configuring the cgd with a random-key (as Alan suggested) and dding
>> /dev/zero to this is the best solution *IF* you want to fill up the image
>> and you always want to write a full image, I agree.
>I'm certainly not a crypto expert, but won't there be some (enough)
>sectors that were sure to have been untouched otherwise and thus which
>an attacker can assume to have been filled with encrypted zeros and, if
>so, will this make it any easier to attack the CGD key?

I don't think that's a real issue.  AES (or any reasonable 
cryptosystem) is very secure against that attack (known in the crypto 
game as a "known plaintext" attack).  

		--Prof. Steven M. Bellovin,