Random password generator in PHP not returning password

Question

I am trying to set up a random password generator function in php but this is not working for me. I get the error:

Notice: Array to string conversion in C:\xampp\htdocs\php-testing\index.php on line 12

Array

What am I doing wrong?

<?php
function pwGenerator($len = 10) {
    $charRange = "abcdefghijklmnopqrstuwxyzABCDEFGHIJKLMNOPQRSTUWXYZ0123456789!@#$%^&*()";
    $pw = array();
    $length = strlen($charRange);
    for ($x = 0; $x < $len; $x++) {
        $n = rand(0, $length);
        $pw[] = $charRange[$n];
    }

    return $pw;
}

echo pwGenerator();

Well, you obviously return an array and then try to echo ... that array. For an echo it would have to be a string. So do this: return implode('', $pw); — arkascha
– arkascha, Commented May 21, 2016 at 6:57

Abhinav · Accepted Answer · 2016-05-21 07:02:49Z

3

You cannot convert array into string directly. So instead of storing it in array you can attach characters with a string. and now it is working.

<?php
    function pwGenerator($len = 10) {
        $charRange = "abcdefghijklmnopqrstuwxyzABCDEFGHIJKLMNOPQRSTUWXYZ0123456789!@#$%^&*()";
        $pw = null;
        $length = strlen($charRange);
        for ($x = 0; $x < $len; $x++) {
            $n = rand(0, $length);
            $pw .= $charRange[$n];
        }
        return $pw;
    }
    echo pwGenerator();
    ?>

answered May 21, 2016 at 7:02

Abhinav

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2 Comments

Marco V Over a year ago

I am still getting this error though: Notice: Uninitialized string offset: 70 in C:\xampp\htdocs\php-testing\index.php on line 8

Abhinav Over a year ago

it is because random selecting 70. And your length of $charRange is 70 and it is only 69 when you put it into array. so you need to reduce 1 from $length,then it will work.

JYoThI · Accepted Answer · 2016-05-21 07:00:01Z

0

try this

you should define $pw as string not array

and $pw.= to concatenate the string sequence like this

<?php


function pwGenerator($len = 10) {
    $charRange = "abcdefghijklmnopqrstuwxyzABCDEFGHIJKLMNOPQRSTUWXYZ0123456789!@#$%^&*()";
    $pw ='';
    $length = strlen($charRange);
    for ($x = 0; $x < $len; $x++) 
    {
        $n = rand(0, $length);

        $pw.= $charRange[$n];
    }

    return $pw;
}

 echo pwGenerator();

?>

edited May 21, 2016 at 7:00

answered May 21, 2016 at 6:57

JYoThI

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7 Comments

arkascha Over a year ago

The additional brackets you added to the echo statement are not required, nor do they help otherwise.

Marco V Over a year ago

Yes this works, but sometimes I am getting this error now: Notice: Uninitialized string offset: 70 in C:\xampp\htdocs\php-testing\index.php on line 12

Andreas Over a year ago

I was just about to write that. It makes no difference? It's still an array, and arrays can't be echoed.

arkascha Over a year ago

@Andreas No, it is indeed a string with that code. Ugly, cause slow, but working.

JYoThI Over a year ago

how you telling that its array ?

|

Will · Accepted Answer · 2016-05-21 07:08:29Z

This is how I would do it. Not only is it fast, it is significantly more random (and thus secure) than some of the others, due to allowing characters to repeat and using mt_rand().

function generateRandomPassword($length = 10)
{
    static $chars = 'abcdefghijklmnopqrstuwxyzABCDEFGHIJKLMNOPQRSTUWXYZ0123456789!@#$%^&*()';
    static $charsLength = strlen($chars);

    $randomPassword = '';
    for ($i = 0; $i < $length; ++$i)
    {
         $randomPassword .= $chars[mt_rand(0, $charsLength - 1)];
    }

    return $randomPassword;
}

Declaring $chars and $charsLength as static may be overkill, but it does result in a performance improvement. Additionally, mt_rand() is more secure than rand().

The original error you received about "array to string conversion" is because you returned an array from your function. If you wanted to fix this, just change:

return $pw;

To:

return implode('', $pw);

Community · Accepted Answer · 2017-05-23 12:23:59Z

0

A faster approach might be to shuffle a character set then grab a string of the proper length.

function random_password( $length = 10 ) {
    $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#$%^&*()_-=+;:,.?";

    $substr_length = 3;
    if( $length > $substr_length ) {

        $password = '';
        while ( strlen($password) < $length) {
            $current_length = strlen( $password );
            $substr_length = ($length - $current_length) > $substr_length ? $length - $current_length : $current_length;
            $password .= substr( str_shuffle( $chars ), 0, $substr_length );
        }

    } else {

        $password = substr( str_shuffle( $chars ), 0, $length );

    }

    return $password;
}

Borrowed from https://stackoverflow.com/a/21768419/2712737

edited May 23, 2017 at 12:23

CommunityBot

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answered May 21, 2016 at 7:00

Tyler Untisz

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3 Comments

arkascha Over a year ago

Actually you first shuffle the input string, then you grab a substring. :-)

Tyler Untisz Over a year ago

Updated verbiage to reflect that. Thanks!

Will Over a year ago

This has very low entropy, as characters cannot repeat.

Denis Bhojvani · Accepted Answer · 2016-05-21 07:27:08Z

0

i think here your mistake is no need to declare $pw as array declare as normal string variable. try below code is working.

<?php
    function pwGenerator($len = 10) {
        $charRange = "abcdefghijklmnopqrstuwxyzABCDEFGHIJKLMNOPQRSTUWXYZ0123456789!@#$%^&*()";
        $pw = "";
        $length = strlen($charRange);
        for ($x = 0; $x < $len; $x++) {
            $n = rand(0, ($length-1));
            $pw .= $charRange[$n];
        }
        return $pw;
    }
    echo pwGenerator();
?>

your are return single password string value so no need to decalre as Array simple declare string variable. may it helps you.

edited May 21, 2016 at 7:27

answered May 21, 2016 at 6:59

Denis Bhojvani

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2 Comments

Marco V Over a year ago

If I carry out stress test on fucntion, I sometimes get: Notice: Uninitialized string offset: 70 in C:\xampp\htdocs\php-testing\index.php on line 8

Denis Bhojvani Over a year ago

@emporio try one trick ($length-1) then you will not get error if your carry out stress test on fucntion you will not get error try like that way for more reference why you need do this trick visit this link stackoverflow.com/questions/15538646/…

Md. Harun Or Rashid · Accepted Answer · 2017-12-03 03:12:22Z

It can be an Easy Solution.

$arr = array('A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'T', 
'W', 'Y', '@', '#', '$', '*', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 
'd', 'e', 'f', 'g', 'h', 'm', 'n', 'p', 'q', 'r', 't', 'u', 'w', 'y', 'z');

$arr2 = array('A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'K', 'L', 'M', 'N', 
'P', 'Q', 'R', 'T', 'W', 'Y', 'a', 'b', 'd', 'e', 'f', 'g', 'h', 'm', 
'n', 'p', 'q', 'r', 't', 'u', 'w', 'y', 'z');

        $rnd = array_random($arr, 4);
        $rnd2 = array_random($arr2, 2);

        $password = $rnd2[0].$rnd[0].$rnd[1].$rnd[2].$rnd[3].$rnd2[1];

The First and the Last character will be only Letter. Middle characters will be Letters, Numbers or Special Characters.

Daro from Poland · Accepted Answer · 2018-05-04 15:03:21Z

0

Reliable passwords You can only make from ascii characters a-zA-Z and numbers 0-9. To do that best way is using only cryptographically secure methods, like random_int() or random_bytes() from PHP7. Rest functions as base64_encode() You can use only as support functions to make reliability of string and change it to ASCII characters.

rand() is not secure and is very old. From any string You must use random_int(). From binary string You should use base64_encode() to make binary string reliable or bin2hex, but then You will cut byte only to 16 positions (values). See my implementation of this functions.

edited May 4, 2018 at 15:03

answered May 1, 2018 at 16:26

Daro from Poland

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Comments

user13745692 · Accepted Answer · 2022-11-06 02:29:01Z

Rashid, that is a good starting direction.

Today, I increased the password length to seven digits, added a few, and corrected the code. I now use this code to generate a random password for a website question generator.

$arr = array('A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm', 'n', 'p', 'q', 'r', 's', 't', 'u', 'w', 'x', 'y', 'z', '@', '#', '$', '*', '!', '%', '&', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0',);

$arr2 = array('A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm', 'n', 'p', 'q', 'r', 's', 't', 'u', 'w', 'x', 'y', 'z');

        $rnd = array_rand($arr, 4);
        $rnd2 = array_rand($arr2, 3);

        $password = $arr2[$rnd2[0]].$arr[$rnd[0]].$arr[$rnd[1]].$arr2[$rnd2[1]].$arr[$rnd[2]].$arr[$rnd[3]].$arr2[$rnd2[2]];

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