1 |
On Donnerstag, 26. Juni 2008, Alan McKinnon wrote: |
2 |
> On Thursday 26 June 2008, Sebastian Wiesner wrote: |
3 |
> > Alan McKinnon <alan.mckinnon@×××××.com> at Thursday 26 June 2008, |
4 |
> > 10:54:43 |
5 |
> > |
6 |
> > > The calculation is quite simple - measure how quickly a specific |
7 |
> > > computer can match keys. Divide this into the size of the keyspace. |
8 |
> > > The average time to brute force a key is half that value. AFAIK |
9 |
> > > this still averages out at enormous numbers of years, even at |
10 |
> > > insane calculation rates like what RoadRunner can achieve. |
11 |
> > |
12 |
> > According to Wikipedia RoadRunner is designed for 1.7 petaflops in |
13 |
> > peak. Assuming for the sake of simplicity, that decryption can be |
14 |
> > performed within a single flop: |
15 |
> > |
16 |
> > (2^256) / (1.7 * 10^15) / 2 ~= 3.5 * 10^61 |
17 |
> > |
18 |
> > In years: |
19 |
> > |
20 |
> > 3.5 * 10^61 / 3600 / 24 / 356 ~= 10^54 |
21 |
> > |
22 |
> > Correct me if I'm wrong, but it seems impossible to me, to reduce |
23 |
> > this get the required amount somewhere near to the life time of a |
24 |
> > human being ;) |
25 |
> |
26 |
> Even with your ultra-liberal assumptions, it still comes out to: |
27 |
> |
28 |
> 1000000000000000000000000000000000000 |
29 |
> |
30 |
> times longer than the entire universe is believed to have existed thus |
31 |
> far (14 billion years). That is an unbelievable stupendously long |
32 |
> period of time. Yeah, I'd agree that brute force is utterly unfeasible |
33 |
> as a vector of attack. Not even the almighty NSA could ever pull that |
34 |
> one off as there simply aren't enough atoms in the universe to make a |
35 |
> supercomputer big enough. |
36 |
> |
37 |
> Numbers don't lie. |
38 |
|
39 |
and this is why nobody uses brute force. |
40 |
|
41 |
There a better ways to crack keys. NSA has tons of experts in mathematics and |
42 |
cryptoanalysis. Plus very sophisticated hardware. I am sure for most ciphers |
43 |
they use something much more efficient than stupid brute force. |
44 |
|
45 |
-- |
46 |
gentoo-user@l.g.o mailing list |