This code allows you to use a changing passowrd based on the day of the week and a present code. Good security in a pinch.

By : drastik

<?
// This page creates a changing password scheme that uses a simple 7 number code that
// changes based on the day of the week. For instance, on monday you would increase the
// first of the seven integers by one, on tuesday you would increase by two, on wendsday:
// increase three, and so on through sunday.
// The php code checks this against you schema of passcodes for each day and determines if
// you have entered the code correctly.

// Given that PHP has a great deal of flexibility in the movement oand find replace
// functions for objects in an array, you can use this code as a starting point to develop
// your own codes. The code above is not unbreakable, a good history buff might even know
// the code itself, but a brute force attack could crack it. Of course, if you are using
// integers, increasing the number of ints will make it ore difficult to crack.

// This code is designged to work like a keypad where no user id is required. You could
// build in userid functionality in your prefeered method (database, textfile, etc) or
// create a code for usernames as well! I've left this part out for the sake of brevity.

if (isset($_POST['passcode'])) { // run the functions if a post is enterd

// This is the passCode function set
$passCode = $_POST['passcode'];
$passCode = explode(".",$passCode); // break the post nto an array
$passCode = array_sum($passCode); // sum the array

// This is the checkCode function set
$baseCode = "8.3.0.4.4.2.1"; // Usualy this is a phone number, easy to remember
$codeArr = explode(".",$baseCode); // array the baseCode

// These functions determine the changes to the code based on the day of the week
if (date("D") == "Mon") {
$codeArr[0] = $codeArr[0] + 1;
}
elseif (date("D") == 'Tue') {
$codeArr[1] = $codeArr[1] + 2;
}
elseif (date("D") == 'Wed') {
$codeArr[2] = $codeArr[2] + 3;
}
elseif (date("D") == 'Thu') {
$codeArr[3] = $codeArr[3] + 4;
}
elseif (date("D") == 'Fri') {
$codeArr[4] = $codeArr[4] + 5;
}
elseif (date("D") == 'Sat') {
$codeArr[5] = $codeArr[5] + 6;
}
elseif (date("D") == 'Sun') {
$codeArr[6] = $codeArr[6] + 7;
}

// bring the changed baseCode numbers back into an array
implode($codeArr);
$sumCode = array_sum($codeArr); // sum that array
if ($sumCode == $passCode) { //check sums for equality
print "Access Granted";} // do whatever once you authorize
else { print "Access Denied!"; }
}

else { //if no post is entered, print the code box
print "Enter code as integers seperated by periods.";
print "<form action=\"$PHP_SELF\" method=\"post\">";
print "<input type=\"password\" name=\"passcode\" />";
print "</form>";
}

?>

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