Generating a 10 digit random confirmation string php

Question

I am trying to create a 'confirmation code' for every user account created on my website and storing it in the db along with their personal information. As you can see in the example below, I tried to generate a random string factoring in the time variable, however, the string is unneccessarily long.

I would like the string to be shorter than the one produced by md5 I was wondering if there is a relatively easy way to generate 10 digit (max) alphanumeric string that has an extremely low collision rate?

What I tried:

  md5(mt_rand(10000,99999).time() . 'example@domain.com');

Output:

0dd6854dba19e70cfda0ab91595e0376

Answer 1

PHP provides the openssl_random_pseudo_bytes function that can be made to securely do what you want.

Do something like:

bin2hex(openssl_random_pseudo_bytes(5))

The above will give you something like e9d196aa14 , for example.

Alternatively, just take the first 10 chars of your existing MD5 string.

Answer 2

http://php.net/manual/en/function.uniqid.php

+

http://br.php.net/manual/en/function.substr.php

Answer 3

This will generate you any random output string from Aa-Zz and 0-9 characters.

function genString($length) {
    $lowercase = "qwertyuiopasdfghjklzxcvbnm";
    $uppercase = "ASDFGHJKLZXCVBNMQWERTYUIOP";
    $numbers = "1234567890";
    $specialcharacters = "{}[];:,./<>?_+~!@#";
    $randomCode = "";
    mt_srand(crc32(microtime()));
    $max = strlen($lowercase) - 1;
    for ($x = 0; $x < abs($length/3); $x++) {
        $randomCode .= $lowercase{mt_rand(0, $max)};
    }
    $max = strlen($uppercase) - 1;
    for ($x = 0; $x < abs($length/3); $x++) {
        $randomCode .= $uppercase{mt_rand(0, $max)};
    }
    $max = strlen($specialcharacters) - 1;
    for ($x = 0; $x < abs($length/3); $x++) {
        $randomCode .= $specialcharacters{mt_rand(0, $max)};
    }
    $max = strlen($numbers) - 1;
    for ($x = 0; $x < abs($length/3); $x++) {
        $randomCode .= $numbers{mt_rand(0, $max)};
    }
    return str_shuffle($randomCode);
}

Usage

$str = genString(10);

Answer 4

I think the best way is

$random = substr(number_format(time() * rand(),0,'',''),0,10); // you can increase the digits by changing 10 to desired digit

Please check it out

Answer 5

尝试使用http://php.net/manual/en/function.str-split.php