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 From:  Ryan Giobbi <rgiobbi at zoominternet dot net>
 To:  Peter Curran <peter at closeconsultants dot com>
 Cc:  Manuel Kasper <mk at neon1 dot net>, m0n0wall at lists dot m0n0 dot ch
 Subject:  Re: [m0n0wall] recommended wireless?
 Date:  Tue, 06 Jul 2004 14:04:25 -0400
I agree with you entirely.

I think the real question is, how valuable is your data? For home use to 
store paper documents/cash, you might have a heavy safe with a 
combinition lock, but typically not a vault rigged with motion 
detectors  and guard dogs :-)

With all of the poeple working from home though, its not hard to imagine 
a very small group of home users that might need something greater.



Peter Curran wrote:

>Ryan
>
>I am well aware of the literature (I am pretty sure Manuel is as well), I even 
>have a copy of 'Cracking DES' that somebody gave me as a joke present a 
>couple of years ago.  The fact remains that you still can't buy a DES-cracker 
>in CompUSA, Frys or equivalent.
>
>If I was managing security for a mega-corp with really sensitive and important 
>data flying around (which is my day job on occasion) then I worry about 
>whether to trust AES-256.  For securing my home network, PLOD (PLain Old DES) 
>is perfectly OK.  If somebody has the knowledge and need to crack it, then 
>they will find many easier ways of getting in.
>
>Peter Curran
>CISSP, CISM, CISA, CCSE
>
>On Tuesday 06 July 2004 18:25, Ryan Giobbi wrote:
>  
>
>>http://en.wikipedia.org/wiki/DES#Vulnerabilities
>>
>>"...a corporation willing to spend 10 million dollars to build a similar
>>device today might break DES dozens if not hundreds of times per hour."
>>
>>I do not know of any more examples other than the few listed in the
>>article in 1999.
>>
>>Peter Curran wrote:
>>    
>>
>>>I think that there are 2 different issues here.
>>>
>>>1.  PBKDF1 (and similar) algorithms (such as the one used by Kerberos -
>>>ISTR this is a different way of doing the same thing) are really designed
>>>at producing a good quality key with minimal entropy.  The idea being
>>>that a simple brute-force attack on the whole key space is not
>>>'short-cuttable'. Whilst they may be successful in achieving that
>>>objective, they will not help if the user selecting the password chooses
>>>a weak example, such as a dictionary word, car registration number or
>>>similar.  (I know that you made the caveat about 'usual precautions', but
>>>the reality is that these are broadly ignored/unenforceable).
>>>
>>>2.  56 bit DES tends to be dismissed as 'too weak'.   Well, I don't know
>>>if you have any knowledge of anybody ever having any DES-encrypted data
>>>compromised by a brute force attack - I certainly don't.  [password
>>>guessing, on the other hand, is sadly familiar].  As you say, a couple of
>>>PC's are not going to help much when it comes to attempting a brute-force
>>>attack on a 56-bit DES encryption.  I think it is a shame that it has
>>>become received wisdom that anything with a key length < 128 bits is bad.
>>> For your average man in the street, 56-bit DES is perfectly adequate and
>>>likely to remain so for a few years yet.  (I had this problem a few days
>>>ago when trying to explain to a company that using plain DES to support
>>>Windows/UNIX integration using Kerberos was OK).  They just did not
>>>accept it!  Why, because they had seen a TV programme where some pundit
>>>had explained that <128-bit == BAD CRYPTO!
>>>
>>>Peter
>>>
>>>On Tuesday 06 July 2004 15:49, Manuel Kasper wrote:
>>>      
>>>
>>>>On 06.07.2004 15:25 +0100, Peter Curran wrote:
>>>>        
>>>>
>>>>>I think encyrption is intriguing as a solution to the
>>>>>confidentiality issues,  but as they are using DES on the Netgear
>>>>>stuff I assume that you have to  pre-configure all the devices with
>>>>>a shared key.  As this tends to be derived  from a passord it could
>>>>>be relatively easy to attack.
>>>>>          
>>>>>
>>>>I did a little analysis of HomePlug powerline networking about a year
>>>>ago. The password hashing is done as per PBKDF1 - it involves using
>>>>MD5 1000 times, so with the usual password precautions in place, the
>>>>resulting 56-bit DES key should be good. Also, provided that the
>>>>implementation in HomePlug doesn't suffer from similar flaws as WEP,
>>>>56-bit encryption is IMHO enough for home users. I mean, it's not
>>>>like you can brute-force-search a 56-bit key in a useful amount of
>>>>time with only a few PCs at hand...
>>>>
>>>>- Manuel
>>>>        
>>>>
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>>
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