10 More Discussions You Might Find Interesting
1. HP-UX
Hi,
In our HP-UX B.11.11. I could not find dev/urandom and dev/random
Are all pseudo-devices implemented as device drivers, or in need to run /configure some package to install the package to have dev/urandom.
Please help (4 Replies)
Discussion started by: rashi
4 Replies
2. Homework & Coursework Questions
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
Write a shell script that will take the sum of two random number?
Ex: Random n1 +Random n2 = result
i tries to write it but i had some dufficulties
... (3 Replies)
Discussion started by: renegade755
3 Replies
3. Shell Programming and Scripting
i want to generate a random number through a script, and even if anyone reads the script, they wont be able to figure out what the random number is. only the person who setup the script would know it.
something like this could work: random
the full thread is here:
... (13 Replies)
Discussion started by: SkySmart
13 Replies
4. Shell Programming and Scripting
I have a for loop that cycles twice and generates 1 random number for each pass through. I would like to be able to store the two numbers to use later for arithmetics. Is there a way to do that? Right now I can only seem to use the last random number for anything. Thanks. (4 Replies)
Discussion started by: AxlVanDamme
4 Replies
5. Shell Programming and Scripting
Hi Can someone help me with this one?
I have string..
(PROC_PROC_ID == 12183) <--PID is dynamic
and i want to replace the PID number with whatever PID from
/opt/hpws/apache32_2/logs/httpd.pid file.
i'm having problem since the PID on the string is dynamic. It may be 2-5 digits or more.
... (5 Replies)
Discussion started by: ryandegreat25
5 Replies
6. Shell Programming and Scripting
Hi,
I am having trouble with generating random numbers. can this be done with awk?
So I have a file that looks like this:
23 30
24 40
26 34
So column1 is start and column2 is end. I want to generate 3 random #'s between start and stop:
So the output will look like this:
... (9 Replies)
Discussion started by: phil_heath
9 Replies
7. Shell Programming and Scripting
Hi Guys I have a script to find Ranomd numbers. But I want to make the file to produce more random. Could u guys help me plz.
In this Script I have the code that generates random in for loop and the range I have specified in my %chromlength
input and out put will be like this
chrno start end... (3 Replies)
Discussion started by: repinementer
3 Replies
8. Shell Programming and Scripting
Hello All,
I want to make a simple script which generate random number from 0 to 1000.
and simply display it.
Plz HELP!!!!!!
Regards,
Waqas Ahmed (2 Replies)
Discussion started by: wakhan
2 Replies
9. Programming
Hi,
I am currently trying to generate multiple random numbers in C for different variable:-
die1=1+(rand()%5);
die2=1+(rand()%5);
die3=1+(rand()%5);
die4=1+(rand()%5);
But I need to contrain the total of die1, die2,die3 and die4 to be 5 as well. If i insert die1+die2+die3+die4=5, i do... (6 Replies)
Discussion started by: ahjiefreak
6 Replies
10. UNIX for Dummies Questions & Answers
Is anyone know some scripts to generate random number without repetition using bash; for example generate 10 different random numbers.
Thanks (8 Replies)
Discussion started by: asal_email
8 Replies
random(7D) Devices random(7D)
NAME
random, urandom - Strong random number generator device
SYNOPSIS
/dev/random
/dev/urandom
DESCRIPTION
The /dev/random and /dev/urandom files are special files that are a source for random bytes generated by the kernel random number generator
device. The /dev/random and /dev/urandom files are suitable for applications requiring high quality random numbers for cryptographic pur-
poses.
The generator device produces random numbers from data and devices available to the kernel and estimates the amount of randomness (or
"entropy") collected from these sources. The entropy level determines the amount of high quality random numbers that are produced at a
given time.
Applications retrieve random bytes by reading /dev/random or /dev/urandom. The /dev/random interface returns random bytes only when suffi-
cient amount of entropy has been collected. If there is no entropy to produce the requested number of bytes, /dev/random blocks until more
entropy can be obtained. Non-blocking I/O mode can be used to disable the blocking behavior. The /dev/random interface also supports
poll(2). Note that using poll(2) will not increase the speed at which random numbers can be read.
Bytes retrieved from /dev/random provide the highest quality random numbers produced by the generator, and can be used to generate long
term keys and other high value keying material.
The /dev/urandom interface returns bytes regardless of the amount of entropy available. It does not block on a read request due to lack of
entropy. While bytes produced by the /dev/urandom interface are of lower quality than bytes produced by /dev/random, they are nonetheless
suitable for less demanding and shorter term cryptographic uses such as short term session keys, paddings, and challenge strings.
Data can be written to /dev/random and /dev/urandom. Data written to either special file is added to the generator's internal state. Data
that is difficult to predict by other users may contribute randomness to the generator state and help improve the quality of future gener-
ated random numbers.
By default, write access is restricted to the super-user. An administrator may change the default read/write restriction by changing the
permissions on the appropriate special files.
/dev/random collects entropy from providers that are registered with the kernel-level cryptographic framework and implement random number
generation routines. The cryptoadm(1M) utility allows an administrator to configure which providers will be used with /dev/random.
ERRORS
EAGAIN O_NDELAY or O_NONBLOCK was set and no random bytes are available for reading from /dev/random.
EINTR A signal was caught while reading and no data was transferred.
ENOXIO open(2) request failed on /dev/random because no entropy provider is available.
FILES
/dev/random
/dev/urandom
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability | SUNWcsr |
+-----------------------------+-----------------------------+
|Interface Stability |Evolving |
+-----------------------------+-----------------------------+
SEE ALSO
cryptoadm(1M), open(2), poll(2), attributes(5)
NOTES
/dev/random can be configured to use only the hardware-based providers registered with the kernel-level cryptographic framework by dis-
abling the software-based provider using cryptoadm(1M). You can also use cryptoadm(1M) to obtain the name of the software-based provider.
Because no entropy is available, disabling all randomness providers causes read(2) and poll(2) on /dev/random to block indefinitely and
results in a warning message being logged and displayed on the system console. However, read(2) and poll(2) on /dev/random continue to work
in this case.
An implementation of the /dev/random and /dev/urandom kernel-based random number generator first appeared in Linux 1.3.30.
A /dev/random interface for Solaris first appeared as part of the CryptoRand implementation.
SunOS 5.10 21 June 2004 random(7D)