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  • Originally posted by Qaridarium
    if you are happy you can make a p2p Cluster of linux users and bruteforce the 256bit aes key...
    "The resources required for a brute force attack scale exponentially with increasing key size, not linearly. As a result, doubling the key size for an algorithm does not simply double the required number of operations, but rather squares them." http://en.wikipedia.org/wiki/Brute_force_attack
    (Someone check if I make a mistake in the following)
    Let's say the amount of transistors in year 0 is k. The amount in year 2 by Moore's law would be 2^1 * k. Original effort required to break the encryption is p. Effort after increasing p by one is p^2. If we assumed the password was crackable with transistors k, then p = k. Let's say i is the amount of two year cycles it takes to catch up after a single increment in password size. 2^i * k = k^2 (divided by k) => 2^i = k <=> i = log2(k). You quickly notice from that that you can't indefinitely keep up with the password length increases. Like if it took a two-billion-transistor CPU to break a password with length n, it would take 61.794705708 years by my calculations before you could create a computer that could break a password with length n+1.
    Last edited by nanonyme; 22 April 2009, 10:35 AM.

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    • NIST sums it up nicely, even at 128 bit

      People 7.00E+09
      Computers per person 10.00
      Computers 1.00E+09
      Combos per second per computer 7.00E+19
      Total combos per second 7.00E+19
      Seconds per year 3.15E+07
      Total combos per year 2.22E+12
      128-bit key combos (*50%) 1.70E+38
      Years to crack 7.66E+25

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      • Originally posted by Qaridarium
        PCGH in germany shows that ATI render shadows korrekt @ crysis and nvidia save shader power and do not render all shadows!

        And so? I just provided you with proof that that type of thing is not limited to nvidia but is rampant among all cards. Hell don't even mix intel and s3 renders into it, they are even worse.

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        • Originally posted by Kano View Post
          Did you see any UVD2 (libamdxvba1) programming examples? I never saw those, but I use VDPAU since serveral month. Currently my CPUs are so fast that I don't need VDPAU anymore on the systems which would support it (Intel Q9300@3GHz or E8400), but before 1080p was really much better with it. AMD waits so long that they could sell cpus instead of gpus as well. After 1-2 years nobody will need h264 accelleration when the minium speed is about 3 ghz for a 50$ cpu.
          That is what I have been saying. They are taking so long to release this that by the time they do it will be a moot point.

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          • Not exactly moot, the poor devs who can't afford / make up a reason to buy a new 50$ cpu (which most likely would also include a completely new set, expensive ddr3 ram and all) would then get the chance for great playback on their -current- computers.

            Which is a nice goal in itself.

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            • Originally posted by Qaridarium
              (Combos per second per computer) = 100 000 !.
              For your information 100 000 combos per second is insignificant. We're talking about easily over 91292051633079798989750131910067116342455228306074 83146366674788070551428931526296681935903540008509 26342401 total amount.

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              • Also another note: the thing about WPA2 is that passwords are weak. If the passwords weren't that weak, WPA2 wouldn't be breakable in a timely manner. WPA2 in itself is not weak, humans are. You're not breaking the AES key there, you are just breaking a password set by a silly human. Key-based authentication would be closer to unbreakable.
                Last edited by nanonyme; 22 April 2009, 06:54 PM.

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                • Originally posted by nanonyme View Post
                  For your information 100 000 combos per second is insignificant. We're talking about easily over 91292051633079798989750131910067116342455228306074 83146366674788070551428931526296681935903540008509 26342401 total amount.

                  That's right, and to top it off that Cuda cracker is only effective against extremely weak passwords.

                  Another great breakdown of real numbers.

                  Brute forcing a 256 bits cryptographic code without any known flaws (like WPA2 AES) means that they should test at worst 2^256 keys and average 2^255 (~ 10^76) keys.
                  Let?s say that they are using a new nVidia GPU with 1000 stream processors running at 10 GHz
                  That is 10^13 instructions per second
                  Now with their magical software they can check 1 key per instruction.
                  So, they can check 10^13 keys per second
                  Even with 1 billion of those GPU (10^9) they can "only" calculate 10^22 key per second (.
                  At that rate, they need 10^51 seconds which is 10^43 years.
                  As a reference, the estimate age of the universe is 10^14 years.

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                  • Originally posted by Qaridarium
                    600000000*365*24*60*60=1,89216^16 valid tests!
                    Oh, cool. So it would take only 48247532784267608970568097787748983353656788171230 145158795634555590179630324741547659478604 years to crack an alphanumeric password with spaces with length 60 by bruteforce methods by your calculations with the grid you visioned. You, sir, are a genious.

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                    • It's a good thing most companies require strong passwords these days, so users write their passwords down on yellow sticky notes or leave them in clear-text files on the PC.
                      Last edited by bridgman; 23 April 2009, 10:34 AM.
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