/prog/ - rand() — World4ch

Name: Anonymous 2011-01-27 16:56

Is it possible to find the seed value if you have several consecutive pseudo-random values from stdlib's rand()?

Name: Anonymous 2011-01-27 16:57

1. depends on whose stdlib
2. no
3. yes

Name: Anonymous 2011-01-27 17:00

Maybe.

Name: Anonymous 2011-01-27 17:00

>>2
This file is part of the GNU C Library.
ISO C99 Standard: 7.20 General utilities <stdlib.h>

Who do you think I am, some kind of CAPITALIST?

Name: Anonymous 2011-01-27 17:25

>>1
Since most of them are table-based and finite, a long enough sequence would work if you have perfect knowledge of the implementation. Consider yourself lucky if you can get it down to roughly O(n) where n = seedvalue, though many should be doable in something like O(n % k) for some (probably large) k dependent on the exact implementation.

Name: Anonymous 2011-01-27 17:55

would it be safer to take a rand() and the posix time, then put it in some one-way function or am I just derping out of my ass now?

Name: Anonymous 2011-01-27 18:03

>>6
posix time is predictable
rand() is predictable unless you have some sort of quantum randomization device
if someone has your 1way function it could be bruteforced anyways.

Inb4 GNU GUID GPL v3

Name: Anonymous 2011-01-27 18:47

>>7
rand() is predictable unless you have some sort of quantum randomization device
your a cretin

Name: Anonymous 2011-01-27 19:42

>>4
glibc is pig disgusting bloat

Name: Anonymous 2011-01-27 20:45

>>9
DIG PISGUSTING

Name: Anonymous 2011-01-27 21:23

PIG DICK-GUSTING

Name: Anonymous 2011-01-28 4:46

>>8
am not

True RANDOM NUMBER Generator Exploiting QUANTUM PHYSICS
http://www.idquantique.com/true-random-number-generator/products-overview.html

Name: Anonymous 2011-01-28 5:38

lol soooo randum xD

Name: Anonymous 2011-01-28 5:40

>>12,13
http://dis.4chan.org/read/prog/1233470194/119,120

Name: Anonymous 2011-01-28 10:06

>>14
http://dis.4chan.org/read/prog/1233470194/119-120 will skip the irrelevant first post.

Name: Anonymous 2011-01-28 10:33

>>15
Thank you.

Name: Anonymous 2011-02-04 14:01

Name: Anonymous 2011-02-04 17:53

Don't change these.

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rand()

1 Name: Anonymous 2011-01-27 16:56

2 Name: Anonymous 2011-01-27 16:57

3 Name: Anonymous 2011-01-27 17:00

4 Name: Anonymous 2011-01-27 17:00

5 Name: Anonymous 2011-01-27 17:25

6 Name: Anonymous 2011-01-27 17:55

7 Name: Anonymous 2011-01-27 18:03

8 Name: Anonymous 2011-01-27 18:47

9 Name: Anonymous 2011-01-27 19:42

10 Name: Anonymous 2011-01-27 20:45

11 Name: Anonymous 2011-01-27 21:23

12 Name: Anonymous 2011-01-28 4:46

13 Name: Anonymous 2011-01-28 5:38

14 Name: Anonymous 2011-01-28 5:40

15 Name: Anonymous 2011-01-28 10:06

16 Name: Anonymous 2011-01-28 10:33

17 Name: Anonymous 2011-02-04 14:01

18 Name: Anonymous 2011-02-04 17:53

Name: Anonymous 2011-01-27 16:56

Name: Anonymous 2011-01-27 16:57

Name: Anonymous 2011-01-27 17:00

Name: Anonymous 2011-01-27 17:00

Name: Anonymous 2011-01-27 17:25

Name: Anonymous 2011-01-27 17:55

Name: Anonymous 2011-01-27 18:03

Name: Anonymous 2011-01-27 18:47

Name: Anonymous 2011-01-27 19:42

Name: Anonymous 2011-01-27 20:45

Name: Anonymous 2011-01-27 21:23

Name: Anonymous 2011-01-28 4:46

Name: Anonymous 2011-01-28 5:38

Name: Anonymous 2011-01-28 5:40

Name: Anonymous 2011-01-28 10:06

Name: Anonymous 2011-01-28 10:33

Name: Anonymous 2011-02-04 14:01

Name: Anonymous 2011-02-04 17:53