How to generate random password with PHP?

Question

Or is there a software to auto generate random passwords?

Answer 1

Just build a string of random a-z, A-Z, 0-9 (or whatever you want) up to the desired length. Here's an example in PHP:

function generatePassword($length = 8) {
    $chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
    $count = mb_strlen($chars);

    for ($i = 0, $result = ''; $i < $length; $i++) {
        $index = rand(0, $count - 1);
        $result .= mb_substr($chars, $index, 1);
    }

    return $result;
}

To optimize, you can define $chars as a static variable or constant in the method (or parent class) if you'll be calling this function many times during a single execution.

Answer 2

I actually wrote myself two libraries that I released under GPL V2.0 for generating passwords of any given strength, feel free to check them out and use them if you like.

Www.projects.semanticalsyntax.com Source is avaliable for both.

Answer 3

$password = hash('sha512', rand());

Shouldn't be too hard to remember. This might be easier to remember though:

$password = substr(hash('sha512',rand()),0,12); // Reduces the size to 12 chars

There's only 16 possible characters being used, but that's still 16^12 possible passwords (at 300,000 passwords/second, it would take 29 years to crack).

Answer 4

I want to play the game. The simplest way would be to do:

function rand_passwd( $length = 8, $chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789' ) {
    return substr( str_shuffle( $chars ), 0, $length );
}

This is pretty much just a modification of the first answer. Specify the characters you want in the second parameters and the length of the password in the first.

Answer 5

Here's a simple solution. It will contain lowercase letters and numbers.

substr(str_shuffle(strtolower(sha1(rand() . time() . "my salt string"))),0, $PASSWORD_LENGTH);

Here's A stronger solution randomly generates the character codes in the desired character range for a random length within a desired range.

function generateRandomPassword() {
  //Initialize the random password
  $password = '';

  //Initialize a random desired length
  $desired_length = rand(8, 12);

  for($length = 0; $length < $desired_length; $length++) {
    //Append a random ASCII character (including symbols)
    $password .= chr(rand(32, 126));
  }

  return $password;
}

Answer 6

I wrote one some time ago. It's not random though. It generates passwords based on hashes of inputs you choose. It might be more useful than a truly random password generator. --> http://trashb.in/pwgen

The implementation of the password generation is in Javascript, so it doesn't post any of your details to me. Feel free to use it and/or grab the code.

Answer 7

You could just use PEAR's Text_Password package - it supports quite a few algorithms for generating them; and frees up your time to go onto something else.