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Posted by maTze on November 1, 2005, 11:19 am
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> On 10/31/2005 4:28 PM, ShadowEyez wrote:
>
>>> Ok, that's an interesting data point. Note my "one try per clock cycle"
>>> example above. Here's that math:
>>>
>>> 333 Mhz = 333,000,000 cycles per second.
>>> 333,000,000 * 3600 (sec/hour) = 1.19*10^12 or 1.19e12
>>> 1.19e12 * 24 (hour/day) = 2.87e13
>>> 2.87e13 * 365 (day/year) = 1.05e16.
>>> If you assume that you can get one try per clock cycle, then this is the
>>> number of tries per year. To figure the number of years, you can
>>> divide, but it's close enough to just subtract exponents.
>>
>>
>> One try per clock cycle is not even close to reality. Depending on the
>> language the code is programmed in, how well the code is written, the
>> CPU speed and design, and the OS you're running, your lucky if you can
>> get 150/sec with aircrack for WPA. From what I've seen of the aircrack
>> code, each "try" involves hashing a chosen password with an ESSID with
>> the HMAC function, meaning there is a lot of overhead with each attempt.
>> If I get 120/sec with a 3.0 ghz, 3e9/120 = 25e6 (25 mhz) per try, not 1
>> hz per try.
>>
> Well, of course. I never really thought the "1 per" example was
> realistic. But it helps to make a point. Your example is slower than
> mine.
>
>>
>>> That's where the "10^30 years" came from" (1.0e30).
>>>
>>> So how can a well funded company do? Assume from your example that they
>>> have software/hardware that is 10 times as fast = 1200 passwords/sec.
>>> They will need 277,500 such machines working together just to get to my
>>> 333 Mhz range.
>>
>>
>> A paranoid person would say NSA has a back-door for both TKIP and AES
>> (the WPA and WPA2 algorithms).
>
>
> Yes, and maybe they do and maybe they don't, but that's not "brute
> force" is it? And does not depend on computing power to solve.
>
> Keep in mind the average time to crack a
>
>> password is statistically 1/2 the time it takes to "run through" all of
>> them.
>>
>
> Which means that the number of years has a pronuncible name. What comes
> after a quadrillion?
>
>> A well funded company would probably have mainframes or clusters with
>> thousands of times more computational power than my laptop.
>
>
> I agree. Perhaps a million times more?
>
> A big
>
>> company with competent programmers and enough computing power could
>> probably break through wireless-anything save WPA2 with EAP-TLS radius
>> and even then...
>>
> And even then, if your password is sufficiently random, and long enough,
> then the million times more computing power reduces the time to brute
> force from 10^30 to 10^24. Using your figure for statistically 1/2 the
> time to solution and it's 10^12 years. Hey, a trillion, I really can
> pronunce that! I'll still be dead when they're done, but I can
> pronounce it!
>
>
>>
>>> Naturally you can slice and dice this anyway you want. Give me more
>>> assumptions and I'll give you another ridiculous number of years (and
>>> $$$) to brute force my password. Actually, I can give you a guaranteed
>>> way to "crack" the passwords on my home network. Calculate the cost to
>>> run a server farm of 277,500 for even one year (make sure that you
>>> include hardware, maintenance, etc. or a fair market lease rate), and
>>> then pay me instead. (Cash only please, I'll be opening new bank
>>> accounts) Remember that even with that install, you are still looking
>>> at 1.0e30 years, and I'll guarantee an answer in much less time. ;-)
>>
>>
>> What a deal ;-)
>>
>> Back to reality: my recommendation for most plp is to pick a big long
>> password and use WPA2 if all your equipment supports it and WPA if not,
>> as setting up a radius server is not for everyone, and WPA support is on
>> most wireless stuff sold these days.
>>
>
> Oh, absolutely! The reason that security gets compromised is because
> the cypher is cracked (WEP), or compromised (NSA Backdoors?) or because
> the users pick their dog's name as the password. Basically if you can
> find a way to pick strong passwords, that's one thing you don't have to
> worry about.
>
> Cheers,
>
> John
i think, this point is clear... but what about quantum computers? seems
to be really unlikely that NSA has some in the very moment :]... but
things can change, eh? i guess they'd be faster this way than guessing
this amount of years (as described above).
however, it will take some time til they get one (if they ever get one).
at least i hope so...
Cheers,
maTze
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