9 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Dear UNIX Friends,
I was wondering if there is a random RGB color generator or any function in any unix platforms.
Please share your ideas.
Thanks (2 Replies)
Discussion started by: jacobs.smith
2 Replies
2. UNIX for Dummies Questions & Answers
There was an upload recently on generating a pseudo-random file when /dev/random does NOT exist.
This does not need /dev/random, /dev/urandom or $RANDOM either...
(I assume $RANDOM relies on the /dev/random device in some way.)
This code uses hexdump just because I like hexdump for ease of... (2 Replies)
Discussion started by: wisecracker
2 Replies
3. Cybersecurity
Here is my new password generation script. The attachment, swordfish.txt, is in dos format. Remember that you need to use dos2unix or flip or something to get it into unix format.
The script is self documenting. It has an extensive help system built-in. And you can run:
swordfish "set... (8 Replies)
Discussion started by: Perderabo
8 Replies
4. Ubuntu
Hi
I am new to expect. Please if any one can help on my issue its really appreciable. here is my issue:
I want expect script for random passwords and random commands generation.
please can anyone help me?
Many Thanks in advance (0 Replies)
Discussion started by: vanid
0 Replies
5. Shell Programming and Scripting
Hi,
I need a script that will generate a set of random strings in sequence, with the ability to predetermine the length, quantity, and alphabet of individual string, and to use the outputs of earlier strings in the sequence to define the parameters of later strings. For examples, I might want... (5 Replies)
Discussion started by: vajrajames
5 Replies
6. Shell Programming and Scripting
I've got a file (numbers.txt) filled with numbers and I want to replace each one of those numbers with a new random number between 0 and 9. This is my script so far:
#!/bin/bash
rand=$(($RANDOM % 9))
sed -i s//$rand/g numbers.txtThe problem that I have is that it replaces each number with just... (2 Replies)
Discussion started by: hellocatfood
2 Replies
7. Shell Programming and Scripting
Hi,
I need to create a table with random sentences. I need lines that are upto 1000 characters in lenght. I need a random sentence generator that will create sentences and output it to a text file. The sentences should be of lenght varying from 1 to 1000.
Does anyone know how this can be... (7 Replies)
Discussion started by: kaushys
7 Replies
8. Solaris
I am trying to find a way to generate random numbers within a shell script.
Does Solaris have a utility that will generate random numbers?
Thanks in advance.
B (3 Replies)
Discussion started by: one_ring99
3 Replies
9. Cybersecurity
I need a great Password Generator program. I looked at a few of them, but none of them seemed to be what I wanted. So I have decided to write my own. (That's the cool thing about being a programmer....I always get what I want in software :) )
Do you have any password generators that you... (13 Replies)
Discussion started by: Perderabo
13 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)