Keeping users logged in without cookie

Question

I was wondering if there was any other way to keep users logged in when they revisit my website even though the session has expired.

I currently use a cookie based method, but I was wondering if there were other methods people are using.

Answer 1

不，cookie旁边没有[可靠]方法。

Answer 2

There are other methods, but you should refrain from using them because they in no way are as reliable as cookies.

• You can use a IP based login system. If using this, you will see issues with multiple users from same IP.
• You can generate a special link for users that is uniquely generated and make a login based on that

Instead of worrying about doing it another way, you should work on making your cookie-using system more secure.

Answer 3

This is a very old question, but for the sake of future visitors, I would like to supply an answer.

You SHOULD use cookies. Like the other answers have noted, they are the most reliable method out there. If you want to make sure the user isn't visiting with an expired cookie, write the time at which it expires as a cookie with a checksum.

Here's an example using PHP:

$expireTime = time() + (60*60*24*3); // 3 days ( 60 seconds * 60 minutes * 24 hours * 3 days )
$rawPepper = openssl_random_pseudo_bytes(16);
$hexPepper = bin2hex($rawPepper);
setCookie($cookieKey, $cookieValue, $expireTime);
setCookie("expiresWhen", $expireTime, $expireTime);
setCookie("rand", $hexPepper, $expireTime);
$hash_1 =  hash('sha512', "Your_Super_Secret_Salt" . $cookieValue . "Another_Super_Secret_Salt!" . $expireTime);
$hash_2 = hash('sha512', "Yet_Another_Salt!" . $hash_1. $hexPepper);
setCookie("checksum", $hash_2, $expireTime);

Then in your other PHP form for validation you say:

$expires = $_COOKIE['expiresWhen'];
$pepper = $_COOKIE['rand'];
$cookieVal = $_COOKIE[$cookieKey];
$givenCheckSum = $_COOKIE['checksum'];

$hash_1 = hash('sha512', "Your_Super_Secret_Salt" . $cookieVal . "Another_Super_Secret_Salt!" . $expires);
$correctCheckSum = hash('sha512', "Yet_Another_Salt!" . $hash_1. $pepper)

if($givenCheckSum != $correctCheckSum){
      /* user's cookie has expired. Handle as you please */
}else{
     /* Cookie is still valid */
}

Anyone care to make corrections to this or supply suggestions?