diff --git a/WireGuard/Shared/Model/Configuration.swift b/WireGuard/Shared/Model/Configuration.swift
index 3e661e6..45c29c1 100644
--- a/WireGuard/Shared/Model/Configuration.swift
+++ b/WireGuard/Shared/Model/Configuration.swift
@@ -4,7 +4,7 @@
 import Foundation
 
 @available(OSX 10.14, iOS 12.0, *)
-class TunnelConfiguration: Codable {
+final class TunnelConfiguration {
     var interface: InterfaceConfiguration
     let peers: [PeerConfiguration]
     init(interface: InterfaceConfiguration, peers: [PeerConfiguration]) {
@@ -55,3 +55,17 @@ struct PeerConfiguration: Codable {
         if (publicKey.count != 32) { fatalError("Invalid public key") }
     }
 }
+
+extension TunnelConfiguration: Encodable { }
+extension TunnelConfiguration: Decodable {
+    enum CodingKeys: CodingKey {
+        case interface
+        case peers
+    }
+    convenience init(from decoder: Decoder) throws {
+        let values = try decoder.container(keyedBy: CodingKeys.self)
+        let interface = try values.decode(InterfaceConfiguration.self, forKey: .interface)
+        let peers = try values.decode([PeerConfiguration].self, forKey: .peers)
+        self.init(interface: interface, peers: peers)
+    }
+}