FlyerTalk Forums - View Single Post - CBP officer gave me a stern warning that my laptop shouldn't have ripped DVD/Blu-ray
Old May 17, 2010, 8:33 pm
  #85  
QUERY
 
Join Date: Sep 2009
Posts: 381
Originally Posted by mre5765
"Makes no difference.

http://www.schneier.com/blog/archive...tack_on_a.html

We also expect that a careful analysis may reduce the complexities. As a preliminary result, we think that the complexity of the attack on AES-256 can be lowered from 2^119 to about 2^110.5 data and time.
Let's focus on time. Let's lower that to 2^110 for simplicity. Let's say with the plaintext the NSA can attempt one decryption operation in one nanosecond (one billionth of a second). Then to find the key takes:
2^110 / ( 10^9 * 3600 * 24 * 365.25 *10^15) = 41 quadrillion years.
Now let's say the NSA has spent $10 trillion to buy enough computers to build a massively parallel key cracker. Let's say each cracker costs just $10. So the NSA has one trillion computers to crack keys. So instead of
41 quadrillion years, the NSA takes a mere 41 thousand years.

And I've been extremely generous in my over estimation of the resources the NSA has. I suspect that it takes at least a microsecond, not a nanosecond, to try to decrypt some ciphertext and compare to the known plaintext. I suspect the NSA has spend closer to $100B on its key cracking hardware. And I suspect a key cracker node is closer to $100. So the number is likely closer to 41,000 * 1000 * 100 * 10, or 41 billion years to crack a key.

As I said, good luck with that."
You are implying that Schneier is somehow the only expert in cryptology and that the methods he used were the only ones that could be used(which he doesn't elaborate on). The NSA probably have some of the best cryptographers working for them. Also, if they have access to the laptop and if a hard drive encryption utility was not used, they will have access to many plaintext files as well. In addition, they have the owner's identity and personal info on him as well.
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