Replicate pass encryption from PHP to JS

Question

I would like to replicate the following PHP code in JS:

    $salted = $raw_pass."{".$salt."}";
    $iterations = 5000;
    $digest = hash('sha512', $salted, true);

    // "stretch" hash
    for ($i = 0; $i < $iterations; $i++) {
        $digest = hash('sha512', $digest.$salted, true);
    }

    return base64_encode($digest);

It's creating a hash from pass and salt, 5000 iterations. This is actually from Symfony's MessageDigestPasswordEncoder (I changed the code a bit for the sake of example, sorry for possible typos).

I want to replicate this in JavaScript and I did this:

var salted = raw_pass + "{" + salt + "}"
var digest = CryptoJS.SHA512(salted);              

for (var i=0;i<5000;i++){
    digest = CryptoJS.SHA512(digest+salted);
}

user.password = CryptoJS.enc.Base64.stringify(digest)

Everything works ok when I create digest (I get the same string on both sides), but after it reiterates, I get different hashes. The symfony side is working, so the problem is somewhere in this JS.

What am I doing wrong?

Later edit: I think I have an idea why this is not working. digest is an object and salted is a string. CryptoJS.SHA512 accepts both, but I don't think digest + salted is not what is expecting.

Answer 1

I think the problem is that in PHP you initialize the loop in 1:

for ($i = 1; $i < $iterations; $i++)

but in JavaScript you initialize the loop in 0:

for (var i=0;i<5000;i++)

Answer 2

I think a problem is in here:

<?php
    $salted = $raw_pass."{"$salt."}";
?>

You forgot a dot ( . ), it should be this:

<?php
    $salted = $raw_pass."{".$salt."}";
?>

Also you start one time with 1 and one time with 0 (see post below)

Answer 3

I could not fix it so I had to change the strategy. Considering I'm encoding already encoded (and salted) data and I'm not providing the whole info to the user, I should be safe.

I changed to SHA1 and I'm using btoa() and atobe() JS functions.

Answer 4

Why don't you just use PBKDF2 since CryptoJS also provides that, it seems.