The tag has no wiki summary.

learn more… | top users | synonyms

0
votes
0answers
13 views

How to identify a website's form parameter

In THC Hydra, when you type Hydra -U you get the following syntax (template): <url>:<form parameters>:<condition string> What I'm wondering is how to determine the form parameter. ...
3
votes
2answers
76 views

Create random data with dd and get “partial read warning”. Is the data after the warning now really random?

I create a 1TB file with random data with dd if=/dev/urandom of=file bs=1M count=1000000. Now I check with kill -SIGUSR1 <PID> the progress and get the following: 691581+0 Datens├Ątze ein ...
7
votes
2answers
457 views

RSA 2048 keypair generation: via openssl 0.5s via gpg 30s, why the difference?

RSA 2048 keypair generation: via openssl 0.5s via gpg 30s, why the difference There are several programs which can gerate RSA public/private keypairs GnuPG/OpenPGP for instance has a wizzard being ...
4
votes
1answer
59 views

measure amount of data read from /dev/random

background I have written a collection of bash scripts (most of them in German only yet but if you are interested; download the archive not the single scripts) which help users create high-quality ...
5
votes
3answers
384 views

Reading from /dev/random does not produce any data

I often use the command cat /dev/urandom | strings --bytes 1 | tr -d '\n\t ' | head --bytes 32 to generate pseudo-random passwords. This doesn't work with /dev/random. Specifically cat ...
4
votes
1answer
60 views

What does this command actually cause?

Once while talking with my friend I was trying to joke that we might stand a better chance of completing our project if we just run loads of random programs and expect one of them to solve our ...
10
votes
4answers
427 views

Shuffle file randomly with some additional constraints

I have a huge music playlist and, while some artists have many albums, others have just one song. I wanted to sort the playlist so the same artist won't play twice in a row, or his songs won't end up ...
4
votes
2answers
183 views

What keeps draining entropy?

If I do watch cat /proc/sys/kernel/random/entropy_avail I see that my systems entropy slowly increases over time, until it reaches the 180-190 range at which point it drops down to around 120-130. The ...
2
votes
1answer
220 views

Use the raspberry pi as a source of entropy for /dev/random

I'm trying to see if I can use my raspberry pi's hardware RNG as a source of entropy for /dev/random. Mostly to see if I can get it to work and find yet another use for this nifty little device. Of ...
2
votes
2answers
82 views

Feeding /dev/random with disk reads etc

Is there any way to feed /dev/random with sufficient entropy? The data doesn't have to be truly random, i.e. I can append time of day with pid and add 27 to it, it doesn't matter I just want to make ...
1
vote
1answer
165 views

Starting rng-tools in SLES guest in VirtualBox

I am trying to start rng-tools in a SLES 11 SP3 installation inside of VirtualBox. vagrant@sles11sp3x64:~> uname -a Linux sles11sp3x64 3.0.93-0.8-default #1 SMP Tue Aug 27 08:44:18 UTC 2013 ...
4
votes
2answers
132 views

How to determine which processes are using how much entropy from /dev/urandom

Doing fuser -v /dev/urandom tells me which processes currently have /dev/urandom open, but only that. Is there any was to determine anything about how much entropy each one is using up over time? ...
0
votes
1answer
73 views

Random bug in Linux

Some time ago, I remember reading an article on randomization in computing, and how random you can actually get a system to be. The article came about, if I'm not mistaken, because of some seemingly ...
0
votes
2answers
61 views

Daemon not running when started over ssh

I'm trying to start the rngd daemon by remotely starting it via ssh. Unfortunately it does not seem to run until I log onto the machine. The command I'm using is: ssh -n -o StrictHostKeyChecking=no ...
15
votes
3answers
725 views

Run commands at random

I want to run one of the two commands C1 and C2 at random. How do I do that on commandline (bash)? Will appreciate if a one-liner is possible.
3
votes
2answers
214 views

Why doesn't `head -c 2 /dev/hwrng` work?

I have an Atmel 97SC3201 in my computer and set the following in the kernel: CONFIG_HW_RANDOM_TPM CONFIG_TCG_TPM CONFIG_TCG_ATMEL /dev has tpm0 and hwrng, but running this command returns the ...
3
votes
3answers
892 views

Fast Way to Randomize HD?

I've read about how to make hard drives secure for encryption, and one of the steps is to write random bits to the drive, in order to make the encrypted data indistinguishable from the rest of the ...
4
votes
1answer
1k views

Writing /dev/random to file?

If you ran the following, what would happen? cat /dev/random > ~/randomFile # don't run Would it be written until the drive runs out of space, or would the system see a problem with this and ...
2
votes
3answers
3k views

Why can't tr read from /dev/urandom on OSX?

A colleague suggested creating a random key via the following command: tr -dc A-Za-z0-9_\!\@\#\$\%\^\&\*\(\)-+= < /dev/urandom | head -c 32 | xargs It gave me the error: tr: Illegal byte ...
1
vote
2answers
808 views

random number needed

I need a command line script that will generate a random integer between 1 and 6. I'm using Ubuntu with bash. I was working on this a couple of months ago using 'bc', but never got it to work ...
0
votes
2answers
206 views

How to generate Zipf-like samples, by using scripting language

Is there any scripting language function (like in python or bash) that samples from a zipf-like distribution, for exponent 0<a<=1. PS: I am aware of existence of a numpy function that can ...
15
votes
2answers
5k views

How can I populate a file with random data?

How can I create a new file and fill it with 1 Gigabyte worth of random data? I need this to test some software. I would prefer to use /dev/random or /dev/urandom.
17
votes
3answers
3k views

Why does dd from /dev/random give different file sizes?

I am running the following command on an ubuntu system: dd if=/dev/random of=rand bs=1K count=2 However, every time I run it, I end up with a file of a different size. Why is this? How can I ...
8
votes
3answers
2k views

Tool for measuring entropy quality?

Is there a tool available for Linux systems that can measure the "quality" of entropy on the system? I know how to count the entropy: cat /proc/sys/kernel/random/entropy_avail And I know that some ...
-1
votes
2answers
1k views

How to generate random IP addresses

$ nmap -n -iR 0 -sL > RANDOM-IPS-TMP.txt $ grep -o "[0-9]*\.[0-9]*\.[0-9]*\.[0-9]*" RANDOM-IPS-TMP.txt | egrep -v "10.*|172.[16-32].*|192.168.*|[224-255].*" > RANDOM-IPS.txt egrep: Invalid ...
6
votes
3answers
689 views

Lightweight utility/program to run a command after a random delay

I need to randomize the time before a given command starts. I realize it's relatively trivial to do this within a script, or to write a "wrapper" script to do this, but I'm wondering if anyone knows a ...
7
votes
1answer
839 views

Is /dev/random data a psuedo-random AES cypher, and where does the entropy come from?

My current understanding of an entropy pool is that it gathers truly random bits of data at a slow rate. I'd like to know how Unix & Linux collect entropy, and how that entropy is used by ...
5
votes
2answers
2k views

dd if=/dev/random is 'randomly' bottlenecked with BIG time lags, but I have no idea why

I get wildly different real times when I run the following command. dd if=/dev/random bs=1k count=1 It doesn' happen for if=/dev/null, nor does it happen for if=/dev/urandom I've run it 500 ...
1
vote
3answers
1k views

How can I randomize file names in a given directory?

Ok, this may sound like an odd request but it really has a good purpose! I have a Panasonic Plasma TV with an SD card slot, via which I can display a slideshow of JPEG photos. This is useful for ...