"Reverse ENS lookup" using php-keccak

Question

I am using kornrunner/php-keccak and I am attempting to do a "reverse lookup" on an ENS name, essentially the same as this question which was never answered. Any thoughts?

Here's my attempt thus far(just trying to hardcode values for now until I can get the right output and then make it dynamic):

<?php
    error_reporting(E_ALL ^ E_WARNING);
    require __DIR__ . '/vendor/autoload.php';
use kornrunner\Keccak;

function namehash(){
    $address = Keccak::hash(Keccak::hash('eth', 256) . Keccak::hash('0x0000000000000000000000000000000000000000000000000000000000000000' . Keccak::hash('vitailk', 256), 256), 256);

    return '0x' . $address;

}
echo namehash();

?>

This results in: 0x267da6af1e43febb9f45470d33bc49a1226840a1f63d387caa402ba7a298a0be

But what I am expecting is: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045

Answer 1

The namehash for vitalik.eth is 0xee6c4522aab0003e8d14cd40a6af439055fd2577951148c14b6cea9a53475835

In your code example there is a typo. The namehash for vitailk.eth is 0xc44dedd48981fda973d391cc14414c3a0cafd3aa6c9ba4d43ba78fa1039789db.

You can generate namehashes (and other ENS related hashes) here. Disclaimer: EthTools.com is my site.

To generate a namehash in PHP using php-keccak (as in your question) your code would look like the following:

    //The base namehash for '' - 0000000000000000000000000000000000000000000000000000000000000000
    $baseNamehash = hex2bin("0000000000000000000000000000000000000000000000000000000000000000");
//The labelhash for 'eth' - 4f5b812789fc606be1b3b16908db13fc7a9adf7ca72641f84d75b47069d3d7f0
$ethLabelhash = hex2bin(\kornrunner\Keccak::hash("eth", 256));

//The namehash for 'eth' - 93cdeb708b7545dc668eb9280176169d1c33cfd8ed6f04690a0bcc88a93fc4ae
$ethNamehash = \kornrunner\Keccak::hash($baseNamehash . $ethLabelhash, 256); 

//The labelhash for vitalik - af2caa1c2ca1d027f1ac823b529d0a67cd144264b2789fa2ea4d63a67c7103cc
$vitalikLabelhash = hex2bin(\kornrunner\Keccak::hash("vitalik", 256));

//The namehash for vitalik.eth - ee6c4522aab0003e8d14cd40a6af439055fd2577951148c14b6cea9a53475835
$vitalikNamehash = \kornrunner\Keccak::hash(hex2bin($ethNamehash) . $vitalikLabelhash, 256);

Your question is not clear though - your function is named namehash and it looks like you are trying to generate a namehash, but your question implies that you want to do a reverse lookup on a name. Reverse resolution requires interfacing with the ENS contracts on the blockchain. I'd recommend you read the documentation on reverse resolution to learn how to do that.