I'm reading up on protecting passwords and want to get feedback on if my code is correct. I'm trying to use blowfish and crypt() together to prevent anyone from decrypting passwords. Also, I have a question. When I store the password, I assume I will have to also store the variable $string so that I can use it again to verify the user when he signs in, correct?
function unique_md5() {
mt_srand(microtime(true)*100000 + memory_get_usage(true));
return md5(uniqid(mt_rand(), true));
}
//unique_md5 returns a random 16 character string
$string = '$2a$07$' . unique_md5();
$password = 'password';
$password = trim($password);
$protected_password = crypt($password, $string);
//then store the variables $string and $protected_password into the database
Blowfish takes a 22 character string for it's salt (that's not including the type and the cost parameter). MD5 returns a 32 character string, which is not accepted by crypt_blowfish. Use proper salts.
No, you don't need to store the salt with the encrypted password, as the encrypted password is returned to you with the salt already prepended. When you verify if a plaintext password matches a crypted password, you only need to check if $crypted_password == crypt($plaintext_password, $crypted_password).
Related
Somebody should pls guide me on how i can fetch out hashed password from database and match the password entered by a user when login in
i used php crypt() function with bcrypt algorithms to hash the password when registrian the user
thank you all in advance
From the documentation:
$hashed_password = crypt('mypassword'); // let the salt be automatically generated
if (crypt($user_input, $hashed_password) == $hashed_password) {
echo "Password verified!";
}
You need to pass in the original hash, otherwise crypt will generate a random salt and the passwords are very unlikely to match. I.e.
//BROKEN - will almost always print "Bugger off!".
$hash = crypt('Hello world');
$attempt = crypt('Hello world');
if($hash === $attempt){
echo "Access granted!";
}else{
echo "Bugger off!";
}
You don't need to "fetch" the hash from the database, you just hash the given password (from a login attempt I assume) and match THAT hash against the password column of a database. if a match is found where the password column matches the hash that you just made AND the username is a match, then the password is valid.
Thank you all, if i really get your explanations you mean i should hash the coming password from a user attempting to login and then compare the hash value with the one in DB
EXAMple
$salt=//the bcrypt algorithms format, cost parameter and the salt goes here, thesame with the one use when registrian
$coming_pass= crypt( $password, $salt)
mysqli_query ( SELECT from user WHERE username= $username AND
password= $coming_pass)
you just send the unencrypted password into the same crypt process as you did with the encrypted password, then they should match.
PHP has built in Options to do that, look at Creating a Hash, and Verifying a Hash
pseudo-code
hashed password = hp
plain text password = p
seed (Random Number generated by server) = s
hash algorithm (md5, sha1, sha256, ...) = hash
Example with Seeded Hash
hp = hash(p + s)
the order you set the seed is not important, as long you do it the same way every time, by Concatenate the password and seed
Example without Seeded Hash
hp = hash(p)
you will need to save the hp and seed, the p should NEVER be saved by the server, as Plain Text Passwords is a security issue.
C# Code Example:
static public bool IsPasswordCorrect(string hp, string seed, string enteredPasword)
{
return (hp == Sha1(String.Concat(enteredPasword, seed)));
}
this way you have no direct way to get the password from the database, and only the actual Client will have the Plaintext Password.
if you want a 2-way encryption algorithm, you will need to look at RSA, but it is way more complicated and requires a lot of knowledge to make secure.
If i use crypt() to hash a password:
$password = "my_password_12345";
$salt = base64_encode(openssl_random_pseudo_bytes(64, $cstrong));
$crypt = crypt($password, $salt);
I get something like this
echo $crypt; //AG6hHvhjwnqpc
So, when I check for the hash I do this and all work fine
echo crypt($password, $crypt); //AG6hHvhjwnqpc
But why the following happens? I do the same check as above but with a password similar to the previous one and I get the same hash.
$password = "my_password_12345_not!";
echo crypt($password, $crypt); //AG6hHvhjwnqpc
I would expect a different hash, but instead I'm getting the same
In PHP, the crypt function use only the 8 first characters :
Extract from the documentation:
The standard DES-based crypt() returns the salt as the first two characters of the output. It also only uses the first eight characters of str, so longer strings that start with the same eight characters will generate the same result (when the same salt is used).
This question already has an answer here:
How to check a mysql encrypt value with a salt in PHP?
(1 answer)
Closed 9 years ago.
I would like to encrypt some passwords and put it in database. How do I keep this stuff in a database so I can retrieve the data if the owner matches.
Example
<?php
// some validations and other staff
$data = $_POST['input'];
$hash = crypt($data);
//then database insert code
?>
If I echo the $hash, it's giving me some encrypted data but when I refresh the page, the numbers are changing from time to time. How do I keep the data static? How will I tell the encrypted password that this was the owner when username and password entered.
Example
<?php
//time of encryption
$name = "someone";
$pass = "p1x6Fui0p>j";
$hash = "$pass"; //outcome of $hash e.g. $1$aD2.bo0.$S93XNfgOFLskhis0qjE.Q/
// $hash and $name inserted in database
?>
When the user tries to login with collect details, how will I refer $hash "$1$aD2.bo0.$S93XNfgOFLskhis0qjE.Q/" was equal to $pass "p1x6Fui0p>j" ?
crypt() has an unfortunate name. It's not an encryption function, but a one-way hashing function.
If you're using PHP 5.5+, just use password_hash and password_verify:
$hash = password_hash($data, PASSWORD_BCRYPT); // Bcrypt is slow, which is good
And to verify the entered password:
if (password_verify($pass, $hash)) {
// The password is correct
}
Now to answer your actual question: the purpose of password hashing is to authenticate users without actually storing their plaintext passwords. If hash(a) == hash(b), then you can be pretty sure that a == b. In your case, you already have hash(a) ($hash), so you just need to hash the inputted password and compare the resulting hashes.
crypt() does this for you:
if (crypt($pass, $hash) === $hash) {
// The password is correct
}
From the php crypt page
if (crypt($user_input, $hashed_password) == $hashed_password) {
echo "Password verified!";
}
You are not using your own salt, so for every call salt is automatically generated, and salted password is hashed. To get the same hash from this password, you need to run crypt with exact salt that was generated during first run.
Generated salt varies depending on algorithm used for hashing, but from your example it's MD5, and salt is delimited by first and third dollar sign inclusively:
$hash = '$1$aD2.bo0.$S93XNfgOFLskhis0qjE.Q/';
// \ salt /
So to get Exact same hash you need to call crypt($pass, '$1$aD2.bo0.$');
Remember that if you want to use your own salt, it needs to be in proper format for given algorithm. For best results use php 5.5+ password_hash mentioned by #Blender, and for older php versions there is password_compat library, with this you don't have to worry about proper salt format.
I have two functions, HashPassword() and ValidatePassword.
The first one hashes the password given on signup form with a dynamic salt and the second validates the password.
Basically, I am checking if the password hashes match they never do match. On my login form when I call the ValidatePassword() function I have tested echoing out the hashes in the ValidatePassword() to make sure I am splitting the hash in write place for comparing and I am but when comparing them, they echo out a different hash.
Probably easier to look at both functions to explain better.
<?php
// hashes a users password along with a dynamic salt
// dynamic salt is stored with users password and is seperated by a ;
function HashPassword($password){
// creates a dynamic salt
$DynamicSalt = uniqid('', true);
// hash the password given from user along with dynamic salt
$HashedPassword = hash('sha512', $password . $DynamicSalt);
// combine the hashed password seperated by ; then the dynamic salt to store in database
$final = $HashedPassword.';'.$DynamicSalt; // this value is stored in database like: c29fc9e4acdd2962c4db3f108bee728cf015c8f6388ab2cd4f21e405f9d2f13b2d53a1ab8629aa21c3453906a98aff0d4b9a0e14bfc2c553a4f9c7c0c32fc58a;4f91cfc746b426.53641182
return $final;
}
// validate password user entered ($password = password from user | $dbHashedPassword = hash from database)
function ValidatePassword($password, $dbHashedPassword){
// we need to get the password hash before the salt, (fetch just the first 128 characters from database hash)
$CorrectHash = substr($dbHashedPassword, 0, 128);
// get the dynamic salt from end of sha512 hash (
$DynamicSalt = substr($dbHashedPassword, 129, 151); // get just the dynamic salt part of the db hash
// hash the password from user and the dynamic salt which we got from the end of the hash from database
$TestHash = hash('sha512', $password . $DynamicSalt);
return ($CorrectHash == $TestHash);
// WHEN I ECHO OUT THE THREE VARIABLES $CorrectHash, $DynamicSalt and $TestHash
// THE $CorrectHash (from db, first 128 chars) is not the same as $TestHash
// AND TO MAKE SURE I AM SPLITTING THE HASH AND DYNAMIC SALT InN THE CORRECT PLACE I ECHO OUT
// $DynamicSalt and it is split in the correct place showing the 23 characters which the dynamic salt is 23 characters
// BUT WHEN I COMBINE THE $password and $DynamicSalt in $TestHash it shows a completely different hash from the $CorrectHash (which we got and split from database)
}
?>
I'm not sure what's wrong, but it seems I'm splitting the hash and dynamic salt in the correct place because when I echo out it shows the first 128 chars (sha512) then the dynamic salt (23 chars) but when echoing out the two 128 chars hashes they do not match (by this I mean they are completely different hashes).
It's probably something to do with how you're splitting the hash you're testing against. For instance, you're trying to get a salt that's 151 characters long.
Try this:
function ValidatePassword($password, $dbHashedPassword) {
list($CorrectHash, $DynamicSalt) = explode(";",$dbHashedPassword,2);
return $CorrectHash == hash("sha512",$password.$DynamicSalt);
}
if all your substr are correct you just forgot to append ";" . $DynamicSalt to the $TestHash
btw. this violates against the first database normalization rule: "values have to be atomic". the salt should be stored in a seperate field.
I don't understand the documentation at php.net. It appears they are using the encrypted version of password as the salt when testing against the original encryption.
When I insert crypt with out the optional second parameter (the salt) I get different encrypted versions of the same password. Is this expected behavior?
However if I insert a second parameter of 'd4' then I get the same encrypted passwords for the same password input. Expected behavior.
Prior to insertion on signup:
$pass = crypt('$pass', 'd4'); // after this I insert $pass into the mysql table
Testing on signin:
$pass = crypt($pass, 'd4'); // after this I test $pass against the mysql table
PHP.net documentation:
<?php
$password = crypt('mypassword'); // let the salt be automatically generated
/* You should pass the entire results of crypt() as the salt for comparing a
password, to avoid problems when different hashing algorithms are used. (As
it says above, standard DES-based password hashing uses a 2-character salt,
but MD5-based hashing uses 12.) */
if (crypt($user_input, $password) == $password) {
echo "Password verified!";
}
?>
How does this work?
Since crypt() only uses the first two characters (or whatever CRYPT_SALT_LENGTH is) of the salt argument, passing in the encrypted password (of which the first characters are the salt originally used to encrypt it) does the right thing.
If no salt argument is passed in, a random salt is generated and used.
If your question is... Is it normal that with certain encryption ciphers you are returned with different encrypted strings for the same password/input? The answer is yes. Not to sure what you are refering to about salt. Salt it just salt. In the end it is a deturant and means nothing. Using passwords or encrypted forms of passwords as salt is not recommended, but using some random hash (base64) of a phrase is commonly used. Let me know if this doesn't any, and I'll try again.