Random Password Generator

Question

The domain server requires that all employees have a strong, random password conforming to the following rules:

• Exactly 15 characters long.
• Keyboard-typeable characters only (as shown in code-type below). Teaching the sales to use ALT+NUMPAD codes is not permitted.
• At least 1 lower case letter: abcdefghijklmnopqrstuvwxyz
• At least 1 upper case letter: ABCDEFGHIJKLMNOPQRSTUVWXYZ
• At least 1 numeric digit: 0123456789
• At least 1 symbol: `~!@#$%^&*()_+-={}|[]\:";'<>?,./

For this purpose IT have commissioned and will be distributing a Random Password Generator to all employees. All employees will be required to use the Random Password Generator. The requirements for the Random Password Generator are, in addition to the password restrictions above:

• It must be able to generate all permutations of all allowable characters.
• It must display the generated password on the screen.
• The code is required to be as small as possible (in bytes).

Please submit your proposed solution within the next week.

Answer 1

PHP 5.5 (230 bytes)

echo preg_replace_callback('/./', function ($a)
{
  return chr([rand(33, 126), rand(48, 57), rand(65, 90), rand(97, 122), ord(str_shuffle('`~!@#$%^&*()_+-={}|[]\:";\'<>?,./')[0])][$a[0]]);
}
, str_shuffle(str_pad('1234', 15, 0)));

Or on one line (211 bytes)

echo preg_replace_callback('/./',function($a){return chr([rand(33,126),rand(48,57),rand(65,90),rand(97,122),ord(str_shuffle('`~!@#$%^&*()_+-={}|[]\:";\'<>?,./')[0])][$a[0]]);},str_shuffle(str_pad('1234',15,0)));

Answer 2

Perl (134 characters)

Perl one-liner::

perl -e 'push @a,map{(33..47,58..64,91..96,123..126)[rand (32)]}1;push @a,map{(65..90)[rand(26)]}1;push @a,map{(97..122)[rand(26)]}1;push @a,map{(48..57)[rand(10)]}1;push @a,map{(33..126)[rand(10)]} 1..11;foreach (@a){print chr($_);}'

The Output:

_Gj2()%%&)$#"%&
$Vn7"#"'#%*&$%(
]Tj2*'%)&"#"#(%

Update:

perl -MList::Util=shuffle -e 'push @a,map{(33..47,58..64,91..96,123..126)[rand (32)]}1;push @a,map{(65..90)[rand(26)]}1;push @a,map{(97..122)[rand(26)]}1;push @a,map{(48..57)[rand(10)]}1;push @a,map{(33..126)[rand(10)]} 1..11; @a=shuffle @a;foreach (@a){print chr($_);}'

Answer 3

Python 3.3 (360 characters)

First generate a random character from each list, to ensure the first rule.
Them add a random sample from the whole group of allowed characters to complete the rest of the password.
Now we have a random sequence of 15 chars (a seed), with at least one of each, but the first 4 are always, in order, a lower, an upper, a numeric and a symbol. So we shuffle the seed, thus allowing all possible and valid passwords to be generated.

from random import sample

lower = 'abcdefghijklmnopqrstuvwxyz'
upper = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
numeric = '0123456789'
symbol = '''`~!@#$%^&*()_+-={}|[]\:";'<>?,./'''

seed = sample(lower, 1) + sample(upper, 1) + sample(numeric, 1) + sample(symbol, 1) +\
   sample(lower + upper + numeric + symbol, 11)
pwd = ''.join(sample(seed, 15))
print(pwd)

Answer 4

F#, 67 66 59 characters

Using the same framework method as the C# solution, but obviously F# is shorter:

Web.Security.Membership.GeneratePassword(15,1)|>printf "%s"

I don't need to specify System, apparently.

Answer 5

Bash (111 bytes)

a=`strings /dev/urandom | head -c 512 | iconv -f utf-8 -t us-ascii//TRANSLIT | tr -d '\n' | head -c 15`
echo $a

Example outputs:

bw?<{qqH$lh}VC2
M)2@(nH9IdkOwYh
x;&_IR)NM7bCNd~

Answer 6

C++11 (489 characters)

#include <algorithm>
#include <iostream>
#include <string>
#include <random>
using namespace std;random_device r;uniform_int_distribution<> d4(0,3),d10(0,9),d26(0,25);
char rc(int t){int i=0;switch(t){case 0:i=48+d10(r);break;case 1:i=32;case 2:i+=65+d26(r);break;case 3:i=33+[](unsigned j){return j<15?j:j<22?j+10:j+68;}(d26(r));}return char(i);}
int main(){string s(15,0);int i=0;for(;i<4;i++){s[i]=rc(i);}for(;i<15;i++){s[i]=rc(d4(r));}random_shuffle(s.begin(),s.end());cout<<s<<endl;}

Update: stripped down from 673 to 489 characters

Answer 7

Perl (73 characters)

sub x{@x=map{chr rand6+6*$_+27%122}1..15;print splice@x,rand@x,1 while@x}

Maybe someone can minify it more..