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PHP Math Exercises: Create a human-readable random string for a captcha

PHP math: Exercise-11 with Solution

Write a PHP function to create a human-readable random string for a captcha.

Sample Solution:

PHP Code:

<?php
  function random_string($length = 5)
{ 
$chars = 'bcdfghjklmnpqrstvwxyzaeiou';

for ($x = 0; $x < $length; $x++)
{
$result .= ($x%2) ? $chars[mt_rand(19, 23)] : $chars[mt_rand(0, 18)];
}

return $result;
}
echo random_string();
?>

Sample Output:

rasyn

Flowchart :

Flowchart: Create a human-readable random string for a captcha

PHP Code Editor:

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PHP: Tips of the Day

SQL injection that gets around mysql_real_escape_string()

Consider the following query:

$iId = mysql_real_escape_string("1 OR 1=1");    
$sSql = "SELECT * FROM table WHERE id = $iId";

mysql_real_escape_string() will not protect you against this. The fact that you use single quotes (' ') around your variables inside your query is what protects you against this. The following is also an option:

$iId = (int)"1 OR 1=1";
$sSql = "SELECT * FROM table WHERE id = $iId";

Ref : https://bit.ly/32q3bJ7