[drakaal]

All.

All encryption is breakable. You aren't choosing an unpickable lock, you are picking how good of a thief it will take to rob you.

A 4096 bit encryption might make it really expensive to attack you, but those old numbers about "it would take a computer 40,000 years to crack" don't matter much in a world where that just means you spin up 160k instances in the cloud for 3 months.

That's a Dollar amount that makes cracking YOUR bank account not worth doing. But if it were the Nuclear launch codes for Russia's arsenal it would not be undoable.

[endeavor]

Your scale is way off.

To brute-force AES-128, if you assume:

- Every person on the planet owns 10 computers.

- There are 7 billion people on the planet.

- Each of these computers can test 1 billion key combinations per second.

- On average, you can crack the key after testing 50% of the possibilities.

Then the earth's population can crack one key in 77,000,000,000,000,000,000,000,000 years.

Source: Seagate, http://dator8.info/pdf/AES/3.pdf

[drakaal]

Here is a better article.

http://www.eetimes.com/document.asp?doc_id=1279619

But they are both still wrong.

A. The rate of Keys per second on both are way low, and B, you don't have to test every combination, Certain combinations will tell you that whole chunks of possibilities are not possible.

In truth most of the time you can narrow the potentials to 1% of the total possible to determine a range for the right answer pretty quickly.

Granted if it was as slow as 77 Billion years .7 billion years is still a long time. But no, these numbers are orders of orders of magnitude wrong.

[tptacek]

160,000 EC2 instances running for years won't make a dent in a 2048 RSA key.

[drakaal]

If you have a large enough table of primes and factors RSA 2048 is only about 5% harder to crack than a 1024.

If you don't have one it is billions of times harder. How large is your Prime table? How large is mine? How large is the NSA's?

[tptacek]

No.