Php Programming Code Examples
Php > Algorithms Code Examples
This code generates an MD5 protected string, which can be used
This code generates an MD5 protected string, which can be used
to hand off to other web pages, or even other sites
<?php
class authticket {
var $secret = "setme"; // you WILL want to change this
var $realm = ""; // the realm of this identity
var $lifetime = 2 * 60 *60; // tickets good for 2 hours
var $authenticated = 0; // the data here is valid iff non-zero
var $identity; // the remote identity, if decoded correctly
var $issue; // the time the ticket was issued
var $remote_addr; // the remote address of the client
var $hash; // the hash value. Probably of little use.
var $autherr; // if verification faild, this contains why
//
// helper function which just zeros out the ticket data
//
function zerodata()
{
$this->authenticated = 0;
$this->identity = "";
$this->issue = 0;
$this->remote_addr = "";
$this->hash = "";
$this->autherr = "";
}
//
// Take a string ($identity) and a time ($time) and the internal
// secret value, and generate a string that can be used to verify
// that the remote user is known to us. The result of this function
// is a single string, that can be passed along in a hidden form
// or even a cookie.
//
// If ($time) is 0, the current time is used instead.
//
// ($identity) _cannot_ contain a ``:'' character. If you need
// one in there, you will have to change it to some sort of escape
// sequence.
//
// Some care should be used. I recommend using this only over SSL,
// unless the actual ticket contents are encrypted using something
// stronger than XOR.
//
function makeauth($identity, $time)
{
global $REMOTE_ADDR;
$this->zerodata();
if ($time == 0)
$time = time();
$ticket_items[] = (string)$time;
$ticket_items[] = $this->realm;
$ticket_items[] = $REMOTE_ADDR;
$ticket_items[] = $identity;
$ticket = implode($ticket_items, ":");
$hash = md5($this->secret . $ticket);
$ticket = $hash . ':' . $ticket;
$this->identity = $identity;
$this->issue = $time;
$this->remote_addr = $REMOTE_ADDR;
$this->hash = $hash;
$this->authenticated = 1; /* data is valid */
$this->autherr = "";
return $ticket;
}
//
// Take a ($ticket) string generated by makeauth(), and a ($time),
// and verify that the ticket is valid and not expired.
//
// If ($time) is 0, the current time will be used.
//
// On error, the function returns the empty string "",
// $authenticated is 0, and $autherr contains the reason
// the authentication failed.
//
// On success, the identity encoded in the ticket is returned,
// $authenticated is non-zero, and $autherr is to be ignored.
//
function checkauth($ticket, $time)
{
global $REMOTE_ADDR;
$this->zerodata();
if ($time == 0)
$time = time();
/*
* Item order: hash time realm remote_addr identity
*/
$ticket_items = explode( ":", $ticket);
/*
* if the remote address doesn't match the one in the ticket,
* drop them.
*/
if ($ticket_items[3] != $REMOTE_ADDR) {
$this->autherr = "Address mismatch";
return "";
}
//
// if we are supposed to check for expired tickets, do that
// here.
//
if ($this->lifetime != 0)
if ($time > (int)$ticket_items[1] + $this->lifetime) {
$this->autherr = "Ticket expired";
return "";
}
//
// make certain that the ticket is not being used before
// it was issued.
//
if ($time < (int)$ticket_items[1]) {
$this->autherr = "Ticket used before issued";
return "";
}
//
// verify that the realms match
//
if ($this->realm != $ticket_items[2]) {
$this->autherr = "Realm mismatch";
return "";
}
//
// This could be done better... Reassemble the components
// of the ticket passed to us, and rehash. Compare this
// to the hash we were sent.
//
$tmp_items[] = $ticket_items[1];
$tmp_items[] = $ticket_items[2];
$tmp_items[] = $ticket_items[3];
$tmp_items[] = $ticket_items[4];
$tmp_ticket = implode($tmp_items, ":");
$hash = md5($this->secret . $tmp_ticket);
if ($hash != $ticket_items[0]) {
$this->autherr = "Integrity check failed";
return "";
}
//
// well, it all checks out. Might as well claim we know
// who this person is.
//
$this->hash = $hash;
$this->issue = $ticket_items[1];
$this->remote_addr = $ticket_items[3];
$this->identity = $ticket_items[4];
$this->authenticated = 1;
return $this->identity;
}
};
?>
