Assets Folder in flutter/ dart folder for client certificate authentication

Question

I am trying to do client certificate authenticiation in dart. But when I compile the app with flutter I keep getting cert.p12 not found. Here is my way of doing certificate authentication.

HttpClient createHttpClient(SecurityContext context) {
final cert = "assets/cert.p12";
final password = "mittal";
final sc = SecurityContext.defaultContext
  ..useCertificateChain(cert, password: password)
  ..usePrivateKey(cert, password: password);
return super.createHttpClient(sc)

My assets folder is at the root of the project and cert.p12 is in it. Please help.

Here is a screenshot of android studio :

The Screenshot

I have read the https://flutter.dev/docs/development/ui/assets-and-images and and added, but still the same problem. Please Help

flutter:
  assets:
    - assets/
    - assets/cert.p12

Answer 1

You actually say this:

String cert = "assets/cert.p12" <-- you don't load the cert, you create a String.

This is an example how it works for me:

final clientCert = await rootBundle.load('assets/cert.p12');

context.useCertificateChainBytes(clientCert.buffer.asUint8List(), password: password);

This is a full example:

class MyHttpOverrides extends HttpOverrides {
  ByteData clientCert;
  ByteData keystore;

  MyHttpOverrides({
    required this.clientCert,
    required this.keystore,
  });

  @override
  HttpClient createHttpClient(SecurityContext? context) {
    context = SecurityContext.defaultContext;

    bool _certificateCheck(truststore, String host, int port) {
      return host == "test.backend.com";
    }

    String password = "password";

    context.useCertificateChainBytes(clientCert.buffer.asUint8List(), password: password);

    context.usePrivateKeyBytes(keystore.buffer.asUint8List(), password: password);

    HttpClient client = super.createHttpClient(context)..badCertificateCallback = (_certificateCheck);

    client..badCertificateCallback = (_certificateCheck);

    return client;
  }
}

And use it like this:

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  
  final clientCert = await rootBundle.load('assets/cert.pem');
  final keystore = await rootBundle.load('assets/key.pem');

  HttpOverrides.global = MyHttpOverrides(
    clientCert: clientCert,
    keystore: keystore,
  );
  runApp(MyApp());
}

These are the imports:

import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';