/prog/ - Quiz — Tinychan BBS

Name: Anonymous 2017-07-17 5:14

Q:What takes more energy:
a.Increment a number from 0 to 2^128-1 using 2^128 increment instructions, with a CPU running at 3GHZ at exact 50 Joules/Seconds(50watt).
b.boil off the oceans on Earth.(defined as 5.58072e30 Joules)

Name: Anonymous 2017-07-17 5:31

The number 5.58072e30 is taken from:
https://www.reddit.com/r/falloutlore/comments/3e4fp8/how_much_energy_would_it_take_to_boil_the_oceans/

Name: Anonymous 2017-07-17 10:02

It's possible that that CPU will die in an arbitrary amount of time before finishing.

Name: Anonymous 2017-07-17 10:06

>>1
incrementing a number from x to y requires y-x increment instructions. to increment from 0 to 2^128-1 you'd need 2^128-1 instructions, not 2^128.

Name: Anonymous 2017-07-17 11:31

>>4
We can exceed the requirements.

Name: Anonymous 2017-07-17 11:51

>>5
50 Watts to increment a counter will do that.

Name: Anonymous 2017-07-17 12:00

>>6
50 Watts at constant 100% CPU load seems reasonable.

Name: Anonymous 2017-07-17 12:08

>>6
The problem you can't "just increment a counter" you need the whole CPU for this to work(hence 50Watts)

Name: Anonymous 2017-07-17 16:18

>>8
As long as you're paying the electric bill for the next 3,000,000,000,000,000,000,000 years, go ahead and use a CPU. Personally, I'd go with an ASIC on this.

Name: Anonymous 2017-07-18 8:10

Yet 128 bit keys in symmetric cryptography is still weak.

Name: Anonymous 2017-07-18 10:29

>>10
Thats because bruteforcing isn't used. More effective techniques lower the computational complexity by many orders of magnitude.

Name: Anonymous 2017-07-18 11:12

>>11
With enough ciphertexts you can easily brute-force and recover some 128 bit keys.

Quiz

1 Name: Anonymous 2017-07-17 5:14

2 Name: Anonymous 2017-07-17 5:31

3 Name: Anonymous 2017-07-17 10:02

4 Name: Anonymous 2017-07-17 10:06

5 Name: Anonymous 2017-07-17 11:31

6 Name: Anonymous 2017-07-17 11:51

7 Name: Anonymous 2017-07-17 12:00

8 Name: Anonymous 2017-07-17 12:08

9 Name: Anonymous 2017-07-17 16:18

10 Name: Anonymous 2017-07-18 8:10

11 Name: Anonymous 2017-07-18 10:29

12 Name: Anonymous 2017-07-18 11:12