Random number generator (device)

Random number generator (device)
You are encouraged to solve this task according to the task description, using any language you may know.

If your system has a means to generate random numbers involving not only a software algorithm (like the /dev/random devices in Unix), show how to obtain a random 32-bit number from that mechanism.

Ada

random.adb: <lang Ada>with Ada.Streams.Stream_IO; with Ada.Text_IO; procedure Random is

  Number : Integer;
  Random_File : Ada.Streams.Stream_IO.File_Type;

begin

  Ada.Streams.Stream_IO.Open (File => Random_File,
                              Mode => Ada.Streams.Stream_IO.In_File,
                              Name => "/dev/random");
  Integer'Read (Ada.Streams.Stream_IO.Stream (Random_File), Number);
  Ada.Streams.Stream_IO.Close (Random_File);
  Ada.Text_IO.Put_Line ("Number:" & Integer'Image (Number));

end Random;</lang>

C

It works on systems having /dev/urandom, like e.g. GNU/Linux <lang c>#include <stdio.h>

1. include <stdint.h>

int main(int argc, char **argv) {

   uint32_t v;
   FILE *r = fopen("/dev/urandom", "r");
   
   if (r != NULL)
   {

size_t br = fread(&v, sizeof(uint32_t), 1, r); printf("%d\n", v); fclose(r);

   }

   return 0;

}</lang>

C#

<lang csharp>using System; using System.Security.Cryptography;

private static int GetRandomInt() {

 int result = 0;
 var rng = new RNGCryptoServiceProvider();
 var buffer = new byte[4];

 rng.GetBytes(buffer);
 result = BitConverter.ToInt32(buffer, 0);

 return result;

}</lang>

Forth

<lang forth>variable rnd

randoms ( n -- )

 s" /dev/random" r/o open-file throw
 swap 0 do
   dup rnd 1 cells rot read-file throw drop
   rnd @ .
 loop
 close-file throw ;</lang>

J

Untested: <lang j>256#.a.i.1!:11'/dev/urandom';0 4</lang>

Fallback: <lang j>256#.a.i.4{.host'dd if=/dev/urandom bs=4 count=1'</lang>

Note: this assumes that J is running on linux.

PicoLisp

<lang PicoLisp>: (in "/dev/urandom" (rd 4)) -> 2917110327</lang>

PureBasic

PureBasic has the source for the random data is the "/dev/urandom" device on Linux or Mac OSX and the "Microsoft Cryptography API" on Windows. <lang PureBasic>If OpenCryptRandom()

 MyRandom = CryptRandom(#MAXLONG)
 CloseCryptRandom()

EndIf</lang>

Python

<lang Python>import random rand = random.SystemRandom() rand.randint(1,10)</lang>

Ruby

<lang Ruby> require 'securerandom' SecureRandom.random_number(1 << 31) </lang>

Tcl

<lang tcl>package require Tcl 8.5

1. Allow override of device name

proc systemRandomInteger Template:Device "/dev/random" {

   set f [open $device "rb"]
   binary scan [read $f 4] "I" x
   close $f
   return $x

}</lang> Usage: <lang tcl>% puts [systemRandomInteger] 636131349</lang>