Author Topic: 2048 bit encryption?  (Read 1880 times)

el_ay_es

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2048 bit encryption?
« on: March 22, 2012, 12:07:02 AM »
I very much appreciate your having recently posted a link to this article:
http://www.wired.com/threatlevel/2012/03/ff_nsadatacenter/2/

According to the article, the U.S. NSA now has no problem decrypting the 128-bit encryption that BolehVPN uses and that is commonly used for https communications, such as with financial institutions.  I have seen that some VPNs offer "European" 2048-bit encryption.  I paid little attention to that at the time, because I thought it unnecessary and because I assume 2048-bit encryption would slow things down more.

Does anyone have any idea whether the NSA has an equally easy time with 2048-bit encryption as with 128-bit encryption?

Offline Reuben

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Re: 2048 bit encryption?
« Reply #1 on: March 22, 2012, 12:20:13 AM »
2048 bit encryption is inaccurate and shows a misunderstanding of the type of encryption. That's not the same thing. The Wilders Post already deals with this :D
Who knows what the NSA is capable of? Even if they have broken all existing ciphers, they would not publish it to maintain the edge.

To me all this talk about higher bit encryption is all redundant. Blowfish has NOT been broken. At least it's not known to be broken. An unbroken cipher means someone has to brute force it meaning trying all possible combinations. Brute forcing a 128 bit key means the following:

Bit
8    2^{8}    <1 nanosecond
40    2^{40}    0.015 milliseconds
56    2^{56}    1 second
64    2^{64}    4 minutes 16 seconds
128    2^{128}    149,745,258,842,898 years
256    2^{256}    50,955,671,114,250,072,156,962,268,275,658,377,807,020,642,877,435,085 years

http://en.wikipedia.org/wiki/Brute-force_attack
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Offline Reuben

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Re: 2048 bit encryption?
« Reply #2 on: March 22, 2012, 12:23:33 AM »
So should it make a difference to me that it takes 149,745,258,842,898 years to crack :P or 50,955,671,114,250,072,156,962,268,275,658,377,807,020,642,877,435,085 years :D

To me, this is really unnecessary and I rather take the real and quantifiable performance benefits of a 128 bit key than the theoretical possibility that a 256 bit key is safer.

Why AES is more popular than Blowfish is because AES is used by the US government. Whether that is a good thing or not I'll leave it up to you. I still like Blowfish cause it's just so fast in encrypting as compared to AES and it's not something I see myself changing in the near future.

Also as per that article:
Quote
There is also a physical argument that a 128-bit symmetric key is computationally secure against brute-force attack. The so-called Landauer limit implied by the laws of physics sets a lower limit on the energy required to perform a computation of kT  · ln 2 per bit erased in a computation, where T is the temperature of the computing device in kelvins, k is the Boltzmann constant, and the natural logarithm of 2 is about 0.693. No irreversible computing device can use less energy than this, even in principle.[2] Thus, in order to simply flip through the possible values for a 128-bit symmetric key (ignoring doing the actual computing to check it) would theoretically require 2128 − 1 bit flips on a conventional processor. If it is assumed that the calculation occurs near room temperature (~300 K) the Von Neumann-Landauer Limit can be applied to estimate the energy required as ~1018 joules, which is equivalent to consuming 30 gigawatts of power for one year. This is equal to 30×109 W×365×24×3600 s = 9.46×1017 J or 262.7 TWh (more than 1/100th of the world energy production). The full actual computation—checking each key to see if you have found a solution—would consume many times this amount.

Whatever that means :D

Of course if quantum computing has been discovered somewhere.....then all ciphers are at risk.

I think we're here to provide good secure encryption combined with speed and efficiency. We can of course beef up encryption higher and higher, but that would mean greater resources expended (and more costs) for questionable increases in security. We all have to find a balance and for now, we are satisfied with the level of encryption on our VPN services.

If someone wants to hide data that is so sensitive that it would involve the world's top experts combined with immense computing power to back it up to decrypt that data (and even then we aren't completely sure they'll break it)...well they shouldn't be buying a USD10.50/month VPN :D But that's my cheeky two cents.
« Last Edit: March 22, 2012, 01:01:03 AM by Reuben »
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Offline Reuben

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Re: 2048 bit encryption?
« Reply #3 on: March 22, 2012, 12:32:22 AM »
Added info:

http://en.wikipedia.org/wiki/Key_size

As of 2003 RSA Security claims that 1024-bit RSA keys are equivalent in strength to 80-bit symmetric keys, 2048-bit RSA keys to 112-bit symmetric keys and 3072-bit RSA keys to 128-bit symmetric keys.

Goes to show that bigger does not mean better.

The RSA encryption (which we also implement) is only one part of the story. It enables the key exchange that enables the symmetric cipher. Kinda technical and would fill a whole book. There's a good book called the Code Book http://puzzles.about.com/library/weekly/aa011012.htm which gives u an easy to understand and fascinating look into what this all means.

Another interesting article on RSA encryption:

http://security.stackexchange.com/questions/4518/how-to-estimate-the-time-needed-to-crack-rsa-encryption

Quote
The current RSA factorization record is for a 768-bit integer, announced in December 2009. It took four years and involved the smartest number theorists currently living on Earth, including Lenstra and Montgomery, who have somewhat god-like status in those circles. I recently learned that the selection of the parameters for a 1024-bit number factorization has begun (that's the "brainy" part); the sieving is technically feasible (it will be expensive and involve years of computation time on many university clusters) but, for the moment, nobody knows how to do the linear reduction part for a 1024-bit integer. So do not expect a 1024-bit break any time soon.

Remember that RSA encryption is used during the negotiation stage to exchange keys. As this is highly technical I think I'll leave it to you to read up on the source links, etc etc since that is beyond the scope of our support.
« Last Edit: March 22, 2012, 12:55:33 AM by Reuben »
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el_ay_es

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Re: 2048 bit encryption?
« Reply #4 on: March 22, 2012, 12:53:26 AM »
Most impressive responses, Reuben.  Thanks!