Flutter Dart Hashing in Proper Way to Authorization (SHA1, SHA256, Base64 format) (php to dart)

Question

I am trying to integrate my flutter app with a payment api (called iyzico). Following the steps with http plugin and cyrpto plugin doesn't produce the desired solution. I wanted to ask you where is my mistake. I can not obtain the encodedstring property as desired. There is a php code to understand it well. First we need to hash a string with following steps.

Example on php:   $string = “some string”;

then we need to hash string with SHA1 (result should be in a raw binary format)

Example on php:  $hashedString=  sha1($string, true);

My solution like this up to now;

 var string = utf8.encode("somestring");
 var hashedstring = sha1.convert(string);

Last step is that encode the hashed string to BASE64 format;

Example on php:   $encodedString = base_64_encode($hashedString);

My solution was;

 Codec<String, String> stringToBase64 = utf8.fuse(base64);
 String encodedString = stringToBase64.encode(hashedstring.toString());

I don't know cryptology and crypto plugin very well and I think that ı could not get the value proper format. Thanks for now

Answer 1

This is how I generated the code challenge for PKCE.

import 'dart:convert';
import 'package:crypto/crypto.dart';

String encryptString(String value) =>
    base64UrlEncode(utf8.encode(sha256.convert(utf8.encode(value)).toString()));

Hope this may give some insights.