im currently trying to understand hashes and salts. As i understand it, it should not be possible to verify a password, if i only have the password and the generated hash(that was generated with a random salt ofc).
So how can the password_verify
function in PHP verify my password, if i dont give it the salt? Is there a hidden variable in the background, that stores it for the php hashing functions?
And if that is the case, how can
doveadm pw -t '{SHA512-CRYPT}$6$myhash...' -p "qwertz"
verify it too, even if i run it on a complety different computer? Thats a tool, that comes with Dovecot(a MDA).
Here is my PHP code, that creates a random salt with 64 chars, combines it with a password, creates a hash and verifies the hash via password_verify()
.
I just started working on the whole hash/salt/pepper
thing today, so there could be a huge flaw in my whole train of thought.
<?php
$password = "qwertz";
$salt = createSalt(64);
$hash = crypt($password, "$6$$salt");
if (password_verify($password, $hash)) {
echo 'Password is valid!';
} else {
echo 'Invalid password.';
}
function createSalt($length){
$chars = "IrhsYyLofUKj4caz0FDBCe2W9NRunTgQvp7qOXmS5GM3EJV6i8tAHdkPbxwl1Z";
$salt="";
for($i=0; $i < $length; $i++){
$newchar = substr($chars, rand(0,strlen($chars)-1),1);
$salt .= $newchar;
}
return $salt;
}
?>