Different hashing results in Dart vs PHP code - php

Question

I'm trying to get this working in flutter and i cant get the same outcome.
My php code prints a diffrent hash then my flutter code. Is it posible to do this in a flutter app?
i have tried to achieve this by running this flutter code. But after 5 hours of reading i gave up and created a stack overflow account.
import 'package:crypto/crypto.dart';
import 'dart:convert'; // for the utf8.encode method
import 'package:http/http.dart' as http;
void main() {
var api = 'https://app.repricer.nl';
var endpoint = '/api/v1/channels/all.json';
var method = 'GET';
var public_key = '';
var private_key = '';
var data = '';
var ms = (new DateTime.now()).millisecondsSinceEpoch;
var timestamp = ms / 1000;
var hash_string = public_key + '|' + method + '|' + endpoint + '|' + data + '|' + timestamp.toString();
var key = utf8.encode(private_key);
var bytes = utf8.encode(hash_string);
var hmacSha256 = new Hmac(sha512, key); // HMAC-SHA256
var digest = hmacSha256.convert(bytes);
print(digest);
}
This is the PHP code that i want to convert to flutter:
$api = 'https://app.repricer.nl';
$endpoint = '/api/v1/channels/all.json';
$method = 'GET';
$public_key = '';
$private_key = '';
// Generate the CURL headers to authenticate our request
$headers = generateHash($public_key, $private_key, $method, $endpoint, $data);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,$api.$endpoint);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
$result = curl_exec($ch);
curl_close($ch);
print_r($result);
function generateHash($public_key, $private_key, $method, $endpoint, $data)
{
$timestamp = date("U");
$hash_string = array($public_key,$method,$endpoint,$data,$timestamp);
$hash = hash_hmac('sha512',implode('|',$hash_string),$private_key);
print ($hash);
return array('X-Auth: '.$public_key, 'X-Hash: '.$hash, 'X-Date: '.$timestamp);
}
I expect the output is the same exept from the timestamp. But i ran it in the same second and it are 2 completly diffrent outcomes.

Answer 1

Your code is correct.
Small fix is just replacing:
ms / 1000 to (ms / 1000).toInt()
I don't see other flaw in Your code.
I've came to that answer after doing test run with constant timestamp parameter: 1572731120
PHP:
$timestamp = 1572731120; //date("U");
$hash_string = array($public_key,$method,$endpoint,$data,$timestamp);
$hash = hash_hmac('sha512',implode('|',$hash_string),$private_key);
Dart
var ms = (new DateTime.now()).millisecondsSinceEpoch;
var timestamp = 1572731120;//(ms / 1000).toInt();
var hash_string = public_key + '|' + method + '|' + endpoint + '|' + data + '|' + timestamp.toString();
var key = utf8.encode(private_key);
var bytes = utf8.encode(hash_string);
var hmacSha256 = new Hmac(sha512, key); // HMAC-SHA256
var digest = hmacSha256.convert(bytes);
which proves that results are equal: