Flutter/Dart: Check if User CA / User certificate is installed

certificate.dart

import 'package:flutter/services.dart';

class CertificateChecker {
  static const platform = MethodChannel('channel/certificate');

  static Future<bool> isCertificateInstalled(String certificateName) async {
    try {
      final bool result =
          await platform.invokeMethod('checkCertificate', {'name': certificateName});
      return result;
    } on PlatformException catch (e) {
      print("Failed to check certificate: '${e.message}'.");
      return false;
    }
  }
}

MainActivity.kt

import android.content.Intent
import android.os.Build
import android.provider.Settings
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugin.common.MethodChannel
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.withContext
import java.security.KeyStore
import java.security.cert.X509Certificate

class MainActivity : FlutterActivity() {
    private val CHANNEL = "channel/certificate"

    override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)
        MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL).setMethodCallHandler { call, result ->
            when (call.method) {
                "checkCertificate" -> {
                    val certificateName = call.argument<String>("name")
                    if (certificateName != null) {
                        kotlinx.coroutines.runBlocking {
                            val isInstalled = isCertificateInstalled(certificateName)
                            result.success(isInstalled)
                        }
                    } else {
                        result.error("INVALID_ARGUMENT", "Certificate name is required", null)
                    }
                }
                else -> {
                    result.notImplemented()
                }
            }
        }
    }

    private suspend fun isCertificateInstalled(certificateName: String): Boolean = withContext(Dispatchers.Default) {
        val userInstalledCaCertificates: List<X509Certificate> = try {
            val keyStore = KeyStore.getInstance("AndroidCAStore")
            keyStore.load(null, null)
            val aliasList = keyStore.aliases().toList().filter { it.startsWith("user") }
            aliasList.map { keyStore.getCertificate(it) as X509Certificate }
        } catch (e: Exception) {
            emptyList()
        }

        userInstalledCaCertificates.any { cert ->
            cert.issuerDN.name.contains(certificateName, ignoreCase = true)
        }
    }
}