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Re: How to protect an encrypted file system for off-line attack?



>
>
>
>---- Original Message ----
>From: cjns1989@gmail.com
>To: debian-user@lists.debian.org
>Subject: Re: How to protect an encrypted file system for off-line
>attack?
>Date: Thu, 26 Feb 2009 18:34:40 -0500
>
>>On Tue, Feb 24, 2009 at 12:56:00AM EST, Ron Johnson wrote:
>>> On 02/23/2009 08:43 PM, Javier wrote:
>>> [snip]
>>> >
>>> >
>>> >As I also have read in the Wikipedia, it is reseonable to crack a
>56bits
>>> >DES, a 64bits AES if you have online access to the machine, and
>probably
>>> >in the future it might be possible to crack a 128bits, even
>offline.
>>> >But, a 256 one? It seems incredible to me. 2^256 is this number:
>>> >
>>> >
>>>
>>11579208923731619542357098500868790785326998466564056403945758400791
>3129639936
>>> >
>>> >which is 10^79 iterations, I can't imagine the amount of power
>needed
>>> >for cracking that...
>>> >Isn't 4x10^80 the amount of atoms in the universe?
>>> 
>>> 25 years ago, I had a KayPro II with CP/M, 64KB RAM and 2 380KB 
>>> FDDs.  (Sun 2s of the same era had a 10MHz MC68010, 4MB RAM and
>cost 
>>> $44,000.)  Now, I've got 131,000x more RAM, 2000x more MHz and
>pair 
>>> of CPUs, and 790x more disk space.
>>> 
>>> What kind of specialized crackers does the NSA have now, and how 
>>> much faster and smaller (thus higher rack density) will they be in
>2035?
>>
>>Sorry to revive and already dead thread .. 
>>
>>I have a naive question. 
>>
>>While your brute force decryption is running, how do you determine
>you
>>have found the "one key" and decide it's time to stop?
>>
>>Among trillions of trillions, when do you know you've hit the
>jackpot?
>>
>>The answer is probably obvious but I just don't see it.
>>
It's not as obvious as you may think.  If you have a copy of both the
plaintext AND the ciphertext then it's clearly obvious (the decrypted
cipher text matches the plaintext).  If you don't then it's the
reverse of Ron's comment (the decrypted version is no longer
gobblygook).
Larry
>>
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>>




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