Create Apple Watch App

Sesame-Watch Watch App/Assets.xcassets/AccentColor.colorset/Contents.json

@@ -0,0 +1,11 @@
+{
+  "colors" : [
+    {
+      "idiom" : "universal"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sesame-Watch Watch App/Assets.xcassets/AppIcon.appiconset/Contents.json

@@ -0,0 +1,13 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "platform" : "watchos",
+      "size" : "1024x1024"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sesame-Watch Watch App/Assets.xcassets/Contents.json

@@ -0,0 +1,6 @@
+{
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sesame-Watch Watch App/ContentView.swift

@@ -0,0 +1,150 @@
+import SwiftUI
+import CryptoKit
+
+struct ContentView: View {
+    
+    @AppStorage("server")
+    var serverPath: String = "https://christophhagen.de/sesame/"
+    
+    @AppStorage("localIP")
+    var localAddress: String = "192.168.178.104/"
+
+    @AppStorage("counter")
+    var nextMessageCounter: Int = 0
+
+    @AppStorage("compensate")
+    var isCompensatingDaylightTime: Bool = false
+    
+    @AppStorage("local")
+    private var useLocalConnection = false
+    
+    @AppStorage("deviceId")
+    private var deviceId: Int = 0
+    
+    @EnvironmentObject
+    var keyManager: KeyManagement
+    
+    @State
+    var state: ClientState = .noKeyAvailable
+    
+    @State
+    private var hasActiveRequest = false
+    
+    let server = Client()
+
+    var buttonBackground: Color {
+        state.allowsAction ?
+            .white.opacity(0.2) :
+            .black.opacity(0.2)
+    }
+
+    let buttonBorderWidth: CGFloat = 3
+
+    var buttonColor: Color {
+        state.allowsAction ? .white : .gray
+    }
+    
+    private let sidePaddingRatio: CGFloat = 0.05
+    private let buttonSizeRatio: CGFloat = 0.9
+
+    private let smallButtonHeight: CGFloat = 50
+
+    private let smallButtonWidth: CGFloat = 120
+
+    private let smallButtonBorderWidth: CGFloat = 1
+    
+    var compensationTime: UInt32 {
+        isCompensatingDaylightTime ? 3600 : 0
+    }
+
+    var isPerformingRequests: Bool {
+        hasActiveRequest ||
+        state == .waitingForResponse
+    }
+    
+    var body: some View {
+        VStack(alignment: .center) {
+            Spacer()
+            GeometryReader { geo in
+                HStack(alignment: .center) {
+                    Spacer()
+                    let buttonWidth = min(geo.size.width, geo.size.height)
+                    Text(state.actionText)
+                        .frame(width: buttonWidth, height: buttonWidth)
+                        .background(buttonBackground)
+                        .cornerRadius(buttonWidth / 2)
+                        .overlay(RoundedRectangle(cornerRadius: buttonWidth / 2)
+                            .stroke(lineWidth: buttonBorderWidth).foregroundColor(buttonColor))
+                        .foregroundColor(buttonColor)
+                        .font(.title)
+                        .disabled(!state.allowsAction)
+                        .onTapGesture(perform: mainButtonPressed)
+                    Spacer()
+                }
+            }
+            Spacer()
+        }
+        .background(state.color)
+        .animation(.easeInOut, value: state.color)
+    }
+    
+    func mainButtonPressed() {
+        guard let key = keyManager.get(.remoteKey),
+              let token = keyManager.get(.authToken)?.data,
+              let deviceId = UInt8(exactly: deviceId) else {
+            return
+        }
+        let count = UInt32(nextMessageCounter)
+        let sentTime = Date()
+        // Add time to compensate that the device is using daylight savings time
+        let content = Message.Content(
+            time: sentTime.timestamp + compensationTime,
+            id: count,
+            device: deviceId)
+        let message = content.authenticate(using: key)
+        let historyItem = HistoryItem(sent: message.content, date: sentTime, local: useLocalConnection)
+        state = .waitingForResponse
+        print("Sending message \(count)")
+        Task {
+            let (newState, responseMessage) = await send(message, authToken: token)
+            let receivedTime = Date.now
+            //responseTime = receivedTime
+            state = newState
+            let finishedItem = historyItem.didReceive(response: newState, date: receivedTime, message: responseMessage?.content)
+            guard let key = keyManager.get(.deviceKey) else {
+                save(historyItem: finishedItem.notAuthenticated())
+                return
+            }
+            guard let responseMessage else {
+                save(historyItem: finishedItem)
+                return
+            }
+            guard responseMessage.isValid(using: key) else {
+                save(historyItem: finishedItem.invalidated())
+                return
+            }
+            
+            nextMessageCounter = Int(responseMessage.content.id)
+            save(historyItem: finishedItem)
+        }
+    }
+    
+    private func send(_ message: Message, authToken: Data) async -> (state: ClientState, response: Message?) {
+        if useLocalConnection {
+            return await server.sendMessageOverLocalNetwork(message, server: localAddress)
+        } else {
+            return await server.send(message, server: serverPath, authToken: authToken)
+        }
+    }
+    
+    private func save(historyItem: HistoryItem) {
+        
+    }
+}
+
+struct ContentView_Previews: PreviewProvider {
+    static var previews: some View {
+        ContentView()
+            .environmentObject(KeyManagement())
+    }
+}

Sesame-Watch Watch App/Date+Extensions.swift

@@ -0,0 +1,12 @@
+import Foundation
+
+extension Date {
+
+    var timestamp: UInt32 {
+        UInt32(timeIntervalSince1970.rounded())
+    }
+
+    init(timestamp: UInt32) {
+        self.init(timeIntervalSince1970: TimeInterval(timestamp))
+    }
+}

Sesame-Watch Watch App/HistoryView.swift

@@ -0,0 +1,13 @@
+import SwiftUI
+
+struct HistoryView: View {
+    var body: some View {
+        Text(/*@START_MENU_TOKEN@*/"Hello, World!"/*@END_MENU_TOKEN@*/)
+    }
+}
+
+struct HistoryView_Previews: PreviewProvider {
+    static var previews: some View {
+        HistoryView()
+    }
+}

Sesame-Watch Watch App/KeyManagement.swift

@@ -0,0 +1,121 @@
+import Foundation
+import CryptoKit
+import SwiftUI
+
+private let localKey: [UInt8] = [
+    0x98, 0x36, 0x91, 0x09, 0x29, 0xa0, 0x54, 0x44,
+    0x03, 0x0c, 0xa5, 0xb4, 0x20, 0x16, 0x10, 0x0d,
+    0xaf, 0x41, 0x9b, 0x26, 0x4f, 0x75, 0xa4, 0x61,
+    0xed, 0x15, 0x0c, 0xb3, 0x06, 0x39, 0x92, 0x59]
+
+
+private let remoteKey: [UInt8] = [
+    0xfa, 0x23, 0xf6, 0x98, 0xea, 0x87, 0x23, 0xa0,
+    0xa0, 0xbe, 0x9a, 0xdb, 0x31, 0x28, 0xcb, 0x7d,
+    0xd3, 0xa5, 0x7b, 0xf0, 0xc0, 0xeb, 0x45, 0x65,
+    0x4d, 0x94, 0x50, 0x1a, 0x2f, 0x6f, 0xeb, 0x70]
+
+private let authToken: [UInt8] = {
+    let s = "Y6QzDK5DaFK1w2oEX5OkzoC0nTqP8w5IxpvWAR1mpro="
+    let t = Data(base64Encoded: s.data(using: .utf8)!)!
+    return Array(t)
+}()
+
+extension KeyManagement {
+
+    enum KeyType: String, Identifiable, CaseIterable {
+
+        case deviceKey = "sesame-device"
+        case remoteKey = "sesame-remote"
+        case authToken = "sesame-remote-auth"
+
+        var id: String {
+            rawValue
+        }
+
+        var displayName: String {
+            switch self {
+            case .deviceKey:
+                return "Device Key"
+            case .remoteKey:
+                return "Remote Key"
+            case .authToken:
+                return "Authentication Token"
+            }
+        }
+
+        var keyLength: SymmetricKeySize {
+            .bits256
+        }
+
+        var usesHashing: Bool {
+            switch self {
+            case .authToken:
+                return true
+            default:
+                return false
+            }
+        }
+    }
+}
+
+extension KeyManagement.KeyType: CustomStringConvertible {
+
+    var description: String {
+        displayName
+    }
+}
+
+final class KeyManagement: ObservableObject {
+
+
+    @Published
+    private(set) var hasRemoteKey = true
+
+    @Published
+    private(set) var hasDeviceKey = true
+
+    @Published
+    private(set) var hasAuthToken = true
+
+    var hasAllKeys: Bool {
+        hasRemoteKey && hasDeviceKey && hasAuthToken
+    }
+
+    init() {}
+
+    func has(_ type: KeyType) -> Bool {
+        switch type {
+        case .deviceKey:
+            return hasDeviceKey
+        case .remoteKey:
+            return hasRemoteKey
+        case .authToken:
+            return hasAuthToken
+        }
+    }
+
+    func get(_ type: KeyType) -> SymmetricKey? {
+        let bytes: [UInt8] = get(type)
+        return SymmetricKey(data: bytes)
+    }
+    
+    private func get(_ type: KeyType) -> [UInt8] {
+        switch type {
+        case .deviceKey:
+            return remoteKey
+        case .remoteKey:
+            return localKey
+        case .authToken:
+            return authToken
+        }
+    }
+
+    func delete(_ type: KeyType) {
+        
+    }
+
+    func generate(_ type: KeyType) {
+        
+    }
+}

Sesame-Watch Watch App/Preview Content/Preview Assets.xcassets/Contents.json

@@ -0,0 +1,6 @@
+{
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Sesame-Watch Watch App/Sesame_WatchApp.swift

@@ -0,0 +1,19 @@
+import SwiftUI
+
+@main
+struct Sesame_Watch_Watch_AppApp: App {
+    
+    let keyManagement = KeyManagement()
+    
+    var body: some Scene {
+        WindowGroup {
+            TabView {
+                ContentView()
+                    .environmentObject(keyManagement)
+                SettingsView()
+                HistoryView()
+            }
+            .tabViewStyle(PageTabViewStyle())
+        }
+    }
+}

Sesame-Watch Watch App/SettingsView.swift

@@ -0,0 +1,19 @@
+import SwiftUI
+
+struct SettingsView: View {
+    var body: some View {
+        ScrollView {
+            VStack {
+                Text(/*@START_MENU_TOKEN@*/"Hello, World!"/*@END_MENU_TOKEN@*/)
+            }
+        }
+        .navigationTitle("Settings")
+    }
+}
+
+struct SettingsView_Previews: PreviewProvider {
+    static var previews: some View {
+        SettingsView()
+            .previewDevice("Apple Watch Series 7 - 41mm")
+    }
+}

Sesame.xcodeproj/project.pbxproj

@@ -14,10 +14,31 @@
 		884A45C5279F4BBE00D6E650 /* KeyManagement.swift in Sources */ = {isa = PBXBuildFile; fileRef = 884A45C4279F4BBE00D6E650 /* KeyManagement.swift */; };
 		884A45C927A43D7900D6E650 /* ClientState.swift in Sources */ = {isa = PBXBuildFile; fileRef = 884A45C827A43D7900D6E650 /* ClientState.swift */; };
 		884A45CB27A464C000D6E650 /* SymmetricKey+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 884A45CA27A464C000D6E650 /* SymmetricKey+Extensions.swift */; };
-		884A45CD27A465F500D6E650 /* Client.swift in Sources */ = {isa = PBXBuildFile; fileRef = 884A45CC27A465F500D6E650 /* Client.swift */; };
 		884A45CF27A5402D00D6E650 /* MessageResult.swift in Sources */ = {isa = PBXBuildFile; fileRef = 884A45CE27A5402D00D6E650 /* MessageResult.swift */; };
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 		8864665229E5939C004FE2BE /* SFSafeSymbols in Frameworks */ = {isa = PBXBuildFile; productRef = 8864665129E5939C004FE2BE /* SFSafeSymbols */; };
+		888362342A80F3F90032BBB2 /* SettingsView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 888362332A80F3F90032BBB2 /* SettingsView.swift */; };
+		888362362A80F4420032BBB2 /* HistoryView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 888362352A80F4420032BBB2 /* HistoryView.swift */; };
+		88E197B229EDC9BC00BF1D19 /* Sesame_WatchApp.swift in Sources */ = {isa = PBXBuildFile; fileRef = 88E197B129EDC9BC00BF1D19 /* Sesame_WatchApp.swift */; };
+		88E197B429EDC9BC00BF1D19 /* ContentView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 88E197B329EDC9BC00BF1D19 /* ContentView.swift */; };
+		88E197B629EDC9BD00BF1D19 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 88E197B529EDC9BD00BF1D19 /* Assets.xcassets */; };
+		88E197B929EDC9BD00BF1D19 /* Preview Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 88E197B829EDC9BD00BF1D19 /* Preview Assets.xcassets */; };
+		88E197C229EDCB0900BF1D19 /* KeyManagement.swift in Sources */ = {isa = PBXBuildFile; fileRef = 88E197C129EDCB0900BF1D19 /* KeyManagement.swift */; };
+		88E197C429EDCC8900BF1D19 /* Client.swift in Sources */ = {isa = PBXBuildFile; fileRef = 884A45CC27A465F500D6E650 /* Client.swift */; };
+		88E197C729EDCCBD00BF1D19 /* Client.swift in Sources */ = {isa = PBXBuildFile; fileRef = 884A45CC27A465F500D6E650 /* Client.swift */; };
+		88E197C829EDCCCE00BF1D19 /* ClientState.swift in Sources */ = {isa = PBXBuildFile; fileRef = 884A45C827A43D7900D6E650 /* ClientState.swift */; };
+		88E197C929EDCCE100BF1D19 /* Message.swift in Sources */ = {isa = PBXBuildFile; fileRef = E24EE77827FF95E00011CFD2 /* Message.swift */; };
+		88E197CC29EDCD4900BF1D19 /* NIOCore in Frameworks */ = {isa = PBXBuildFile; productRef = 88E197CB29EDCD4900BF1D19 /* NIOCore */; };
+		88E197CE29EDCD7500BF1D19 /* CBORCoding in Frameworks */ = {isa = PBXBuildFile; productRef = 88E197CD29EDCD7500BF1D19 /* CBORCoding */; };
+		88E197D029EDCD7D00BF1D19 /* SFSafeSymbols in Frameworks */ = {isa = PBXBuildFile; productRef = 88E197CF29EDCD7D00BF1D19 /* SFSafeSymbols */; };
+		88E197D129EDCE5F00BF1D19 /* Data+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = E24EE77127FDCCC00011CFD2 /* Data+Extensions.swift */; };
+		88E197D229EDCE6600BF1D19 /* RouteAPI.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2C5C1DA2806FE8900769EF6 /* RouteAPI.swift */; };
+		88E197D329EDCE6E00BF1D19 /* MessageResult.swift in Sources */ = {isa = PBXBuildFile; fileRef = 884A45CE27A5402D00D6E650 /* MessageResult.swift */; };
+		88E197D429EDCE7600BF1D19 /* UInt32+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2C5C1DC281B3AC400769EF6 /* UInt32+Extensions.swift */; };
+		88E197D529EDCE8800BF1D19 /* ServerMessage.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2C5C1F7281E769F00769EF6 /* ServerMessage.swift */; };
+		88E197D729EDCFE800BF1D19 /* Date+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 88E197D629EDCFE800BF1D19 /* Date+Extensions.swift */; };
+		88E197D829EDD13B00BF1D19 /* SymmetricKey+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 884A45CA27A464C000D6E650 /* SymmetricKey+Extensions.swift */; };
+		88E197D929EDD14D00BF1D19 /* HistoryItem.swift in Sources */ = {isa = PBXBuildFile; fileRef = E28DED34281EB17600259690 /* HistoryItem.swift */; };
 		E24EE77227FDCCC00011CFD2 /* Data+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = E24EE77127FDCCC00011CFD2 /* Data+Extensions.swift */; };
 		E24EE77427FF95920011CFD2 /* DeviceResponse.swift in Sources */ = {isa = PBXBuildFile; fileRef = E24EE77327FF95920011CFD2 /* DeviceResponse.swift */; };
 		E24EE77727FF95C00011CFD2 /* NIOCore in Frameworks */ = {isa = PBXBuildFile; productRef = E24EE77627FF95C00011CFD2 /* NIOCore */; };
@@ -44,6 +65,15 @@
 		884A45CA27A464C000D6E650 /* SymmetricKey+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "SymmetricKey+Extensions.swift"; sourceTree = "<group>"; };
 		884A45CC27A465F500D6E650 /* Client.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Client.swift; sourceTree = "<group>"; };
 		884A45CE27A5402D00D6E650 /* MessageResult.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MessageResult.swift; sourceTree = "<group>"; };
+		888362332A80F3F90032BBB2 /* SettingsView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SettingsView.swift; sourceTree = "<group>"; };
+		888362352A80F4420032BBB2 /* HistoryView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = HistoryView.swift; sourceTree = "<group>"; };
+		88E197AC29EDC9BC00BF1D19 /* Sesame-Watch Watch App.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = "Sesame-Watch Watch App.app"; sourceTree = BUILT_PRODUCTS_DIR; };
+		88E197B129EDC9BC00BF1D19 /* Sesame_WatchApp.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Sesame_WatchApp.swift; sourceTree = "<group>"; };
+		88E197B329EDC9BC00BF1D19 /* ContentView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ContentView.swift; sourceTree = "<group>"; };
+		88E197B529EDC9BD00BF1D19 /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
+		88E197B829EDC9BD00BF1D19 /* Preview Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = "Preview Assets.xcassets"; sourceTree = "<group>"; };
+		88E197C129EDCB0900BF1D19 /* KeyManagement.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = KeyManagement.swift; sourceTree = "<group>"; };
+		88E197D629EDCFE800BF1D19 /* Date+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Date+Extensions.swift"; sourceTree = "<group>"; };
 		E24EE77127FDCCC00011CFD2 /* Data+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Data+Extensions.swift"; sourceTree = "<group>"; };
 		E24EE77327FF95920011CFD2 /* DeviceResponse.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DeviceResponse.swift; sourceTree = "<group>"; };
 		E24EE77827FF95E00011CFD2 /* Message.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Message.swift; sourceTree = "<group>"; };
@@ -70,6 +100,16 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		88E197A929EDC9BC00BF1D19 /* Frameworks */ = {
+			isa = PBXFrameworksBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				88E197D029EDCD7D00BF1D19 /* SFSafeSymbols in Frameworks */,
+				88E197CE29EDCD7500BF1D19 /* CBORCoding in Frameworks */,
+				88E197CC29EDCD4900BF1D19 /* NIOCore in Frameworks */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 /* End PBXFrameworksBuildPhase section */
 
 /* Begin PBXGroup section */
@@ -77,7 +117,9 @@
 			isa = PBXGroup;
 			children = (
 				884A45B5279F48C100D6E650 /* Sesame */,
+				88E197B029EDC9BC00BF1D19 /* Sesame-Watch Watch App */,
 				884A45B4279F48C100D6E650 /* Products */,
+				88E197CA29EDCD4900BF1D19 /* Frameworks */,
 			);
 			sourceTree = "<group>";
 		};
@@ -85,6 +127,7 @@
 			isa = PBXGroup;
 			children = (
 				884A45B3279F48C100D6E650 /* Sesame.app */,
+				88E197AC29EDC9BC00BF1D19 /* Sesame-Watch Watch App.app */,
 			);
 			name = Products;
 			sourceTree = "<group>";
@@ -102,8 +145,8 @@
 				E28DED36281EC7FB00259690 /* HistoryManager.swift */,
 				E28DED2C281E840B00259690 /* SettingsView.swift */,
 				E28DED2E281E8A0500259690 /* SingleKeyView.swift */,
-				884A45CC27A465F500D6E650 /* Client.swift */,
 				884A45C827A43D7900D6E650 /* ClientState.swift */,
+				884A45CC27A465F500D6E650 /* Client.swift */,
 				884A45C4279F4BBE00D6E650 /* KeyManagement.swift */,
 				884A45CA27A464C000D6E650 /* SymmetricKey+Extensions.swift */,
 				884A45BA279F48C300D6E650 /* Assets.xcassets */,
@@ -120,6 +163,36 @@
 			path = "Preview Content";
 			sourceTree = "<group>";
 		};
+		88E197B029EDC9BC00BF1D19 /* Sesame-Watch Watch App */ = {
+			isa = PBXGroup;
+			children = (
+				88E197B129EDC9BC00BF1D19 /* Sesame_WatchApp.swift */,
+				88E197B329EDC9BC00BF1D19 /* ContentView.swift */,
+				888362332A80F3F90032BBB2 /* SettingsView.swift */,
+				888362352A80F4420032BBB2 /* HistoryView.swift */,
+				88E197C129EDCB0900BF1D19 /* KeyManagement.swift */,
+				88E197B529EDC9BD00BF1D19 /* Assets.xcassets */,
+				88E197B729EDC9BD00BF1D19 /* Preview Content */,
+				88E197D629EDCFE800BF1D19 /* Date+Extensions.swift */,
+			);
+			path = "Sesame-Watch Watch App";
+			sourceTree = "<group>";
+		};
+		88E197B729EDC9BD00BF1D19 /* Preview Content */ = {
+			isa = PBXGroup;
+			children = (
+				88E197B829EDC9BD00BF1D19 /* Preview Assets.xcassets */,
+			);
+			path = "Preview Content";
+			sourceTree = "<group>";
+		};
+		88E197CA29EDCD4900BF1D19 /* Frameworks */ = {
+			isa = PBXGroup;
+			children = (
+			);
+			name = Frameworks;
+			sourceTree = "<group>";
+		};
 		E2C5C1D92806FE4A00769EF6 /* API */ = {
 			isa = PBXGroup;
 			children = (
@@ -159,6 +232,28 @@
 			productReference = 884A45B3279F48C100D6E650 /* Sesame.app */;
 			productType = "com.apple.product-type.application";
 		};
+		88E197AB29EDC9BC00BF1D19 /* Sesame-Watch Watch App */ = {
+			isa = PBXNativeTarget;
+			buildConfigurationList = 88E197BF29EDC9BD00BF1D19 /* Build configuration list for PBXNativeTarget "Sesame-Watch Watch App" */;
+			buildPhases = (
+				88E197A829EDC9BC00BF1D19 /* Sources */,
+				88E197A929EDC9BC00BF1D19 /* Frameworks */,
+				88E197AA29EDC9BC00BF1D19 /* Resources */,
+			);
+			buildRules = (
+			);
+			dependencies = (
+			);
+			name = "Sesame-Watch Watch App";
+			packageProductDependencies = (
+				88E197CB29EDCD4900BF1D19 /* NIOCore */,
+				88E197CD29EDCD7500BF1D19 /* CBORCoding */,
+				88E197CF29EDCD7D00BF1D19 /* SFSafeSymbols */,
+			);
+			productName = "Sesame-Watch Watch App";
+			productReference = 88E197AC29EDC9BC00BF1D19 /* Sesame-Watch Watch App.app */;
+			productType = "com.apple.product-type.application";
+		};
 /* End PBXNativeTarget section */
 
 /* Begin PBXProject section */
@@ -166,13 +261,16 @@
 			isa = PBXProject;
 			attributes = {
 				BuildIndependentTargetsInParallel = 1;
-				LastSwiftUpdateCheck = 1320;
+				LastSwiftUpdateCheck = 1430;
 				LastUpgradeCheck = 1320;
 				TargetAttributes = {
 					884A45B2279F48C100D6E650 = {
 						CreatedOnToolsVersion = 13.2.1;
 						LastSwiftMigration = 1430;
 					};
+					88E197AB29EDC9BC00BF1D19 = {
+						CreatedOnToolsVersion = 14.3;
+					};
 				};
 			};
 			buildConfigurationList = 884A45AE279F48C100D6E650 /* Build configuration list for PBXProject "Sesame" */;
@@ -194,6 +292,7 @@
 			projectRoot = "";
 			targets = (
 				884A45B2279F48C100D6E650 /* Sesame */,
+				88E197AB29EDC9BC00BF1D19 /* Sesame-Watch Watch App */,
 			);
 		};
 /* End PBXProject section */
@@ -208,6 +307,15 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		88E197AA29EDC9BC00BF1D19 /* Resources */ = {
+			isa = PBXResourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				88E197B929EDC9BD00BF1D19 /* Preview Assets.xcassets in Resources */,
+				88E197B629EDC9BD00BF1D19 /* Assets.xcassets in Resources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 /* End PBXResourcesBuildPhase section */
 
 /* Begin PBXSourcesBuildPhase section */
@@ -221,7 +329,6 @@
 				E28DED37281EC7FB00259690 /* HistoryManager.swift in Sources */,
 				E2C5C1DB2806FE8900769EF6 /* RouteAPI.swift in Sources */,
 				E2C5C1DD281B3AC400769EF6 /* UInt32+Extensions.swift in Sources */,
-				884A45CD27A465F500D6E650 /* Client.swift in Sources */,
 				E24EE77227FDCCC00011CFD2 /* Data+Extensions.swift in Sources */,
 				E24EE77427FF95920011CFD2 /* DeviceResponse.swift in Sources */,
 				884A45CB27A464C000D6E650 /* SymmetricKey+Extensions.swift in Sources */,
@@ -232,11 +339,35 @@
 				E28DED33281EB15B00259690 /* HistoryListItem.swift in Sources */,
 				E28DED2D281E840B00259690 /* SettingsView.swift in Sources */,
 				884A45B7279F48C100D6E650 /* SesameApp.swift in Sources */,
+				88E197C429EDCC8900BF1D19 /* Client.swift in Sources */,
 				884A45C5279F4BBE00D6E650 /* KeyManagement.swift in Sources */,
 				E2C5C1F8281E769F00769EF6 /* ServerMessage.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		88E197A829EDC9BC00BF1D19 /* Sources */ = {
+			isa = PBXSourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				888362342A80F3F90032BBB2 /* SettingsView.swift in Sources */,
+				88E197B429EDC9BC00BF1D19 /* ContentView.swift in Sources */,
+				888362362A80F4420032BBB2 /* HistoryView.swift in Sources */,
+				88E197D329EDCE6E00BF1D19 /* MessageResult.swift in Sources */,
+				88E197D529EDCE8800BF1D19 /* ServerMessage.swift in Sources */,
+				88E197D129EDCE5F00BF1D19 /* Data+Extensions.swift in Sources */,
+				88E197D229EDCE6600BF1D19 /* RouteAPI.swift in Sources */,
+				88E197D729EDCFE800BF1D19 /* Date+Extensions.swift in Sources */,
+				88E197C829EDCCCE00BF1D19 /* ClientState.swift in Sources */,
+				88E197B229EDC9BC00BF1D19 /* Sesame_WatchApp.swift in Sources */,
+				88E197C929EDCCE100BF1D19 /* Message.swift in Sources */,
+				88E197D929EDD14D00BF1D19 /* HistoryItem.swift in Sources */,
+				88E197C729EDCCBD00BF1D19 /* Client.swift in Sources */,
+				88E197D429EDCE7600BF1D19 /* UInt32+Extensions.swift in Sources */,
+				88E197D829EDD13B00BF1D19 /* SymmetricKey+Extensions.swift in Sources */,
+				88E197C229EDCB0900BF1D19 /* KeyManagement.swift in Sources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 /* End PBXSourcesBuildPhase section */
 
 /* Begin XCBuildConfiguration section */
@@ -423,6 +554,68 @@
 			};
 			name = Release;
 		};
+		88E197BD29EDC9BD00BF1D19 /* Debug */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				ASSETCATALOG_COMPILER_GLOBAL_ACCENT_COLOR_NAME = AccentColor;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++20";
+				CODE_SIGN_STYLE = Automatic;
+				CURRENT_PROJECT_VERSION = 1;
+				DEVELOPMENT_ASSET_PATHS = "\"Sesame-Watch Watch App/Preview Content\"";
+				DEVELOPMENT_TEAM = H8WR4M6QQ4;
+				ENABLE_PREVIEWS = YES;
+				GENERATE_INFOPLIST_FILE = YES;
+				INFOPLIST_KEY_CFBundleDisplayName = "Sesame-Watch";
+				INFOPLIST_KEY_UISupportedInterfaceOrientations = "UIInterfaceOrientationPortrait UIInterfaceOrientationPortraitUpsideDown";
+				INFOPLIST_KEY_WKWatchOnly = YES;
+				LD_RUNPATH_SEARCH_PATHS = (
+					"$(inherited)",
+					"@executable_path/Frameworks",
+				);
+				MARKETING_VERSION = 1.0;
+				PRODUCT_BUNDLE_IDENTIFIER = "de.christophhagen.Sesame-Watch.watchkitapp";
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				SDKROOT = watchos;
+				SKIP_INSTALL = YES;
+				SWIFT_EMIT_LOC_STRINGS = YES;
+				SWIFT_VERSION = 5.0;
+				TARGETED_DEVICE_FAMILY = 4;
+				WATCHOS_DEPLOYMENT_TARGET = 9.4;
+			};
+			name = Debug;
+		};
+		88E197BE29EDC9BD00BF1D19 /* Release */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				ASSETCATALOG_COMPILER_GLOBAL_ACCENT_COLOR_NAME = AccentColor;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++20";
+				CODE_SIGN_STYLE = Automatic;
+				CURRENT_PROJECT_VERSION = 1;
+				DEVELOPMENT_ASSET_PATHS = "\"Sesame-Watch Watch App/Preview Content\"";
+				DEVELOPMENT_TEAM = H8WR4M6QQ4;
+				ENABLE_PREVIEWS = YES;
+				GENERATE_INFOPLIST_FILE = YES;
+				INFOPLIST_KEY_CFBundleDisplayName = "Sesame-Watch";
+				INFOPLIST_KEY_UISupportedInterfaceOrientations = "UIInterfaceOrientationPortrait UIInterfaceOrientationPortraitUpsideDown";
+				INFOPLIST_KEY_WKWatchOnly = YES;
+				LD_RUNPATH_SEARCH_PATHS = (
+					"$(inherited)",
+					"@executable_path/Frameworks",
+				);
+				MARKETING_VERSION = 1.0;
+				PRODUCT_BUNDLE_IDENTIFIER = "de.christophhagen.Sesame-Watch.watchkitapp";
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				SDKROOT = watchos;
+				SKIP_INSTALL = YES;
+				SWIFT_EMIT_LOC_STRINGS = YES;
+				SWIFT_VERSION = 5.0;
+				TARGETED_DEVICE_FAMILY = 4;
+				WATCHOS_DEPLOYMENT_TARGET = 9.4;
+			};
+			name = Release;
+		};
 /* End XCBuildConfiguration section */
 
 /* Begin XCConfigurationList section */
@@ -444,6 +637,15 @@
 			defaultConfigurationIsVisible = 0;
 			defaultConfigurationName = Release;
 		};
+		88E197BF29EDC9BD00BF1D19 /* Build configuration list for PBXNativeTarget "Sesame-Watch Watch App" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				88E197BD29EDC9BD00BF1D19 /* Debug */,
+				88E197BE29EDC9BD00BF1D19 /* Release */,
+			);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
 /* End XCConfigurationList section */
 
 /* Begin XCRemoteSwiftPackageReference section */
@@ -484,6 +686,21 @@
 			package = 8864665029E5939C004FE2BE /* XCRemoteSwiftPackageReference "SFSafeSymbols" */;
 			productName = SFSafeSymbols;
 		};
+		88E197CB29EDCD4900BF1D19 /* NIOCore */ = {
+			isa = XCSwiftPackageProductDependency;
+			package = E24EE77527FF95C00011CFD2 /* XCRemoteSwiftPackageReference "swift-nio" */;
+			productName = NIOCore;
+		};
+		88E197CD29EDCD7500BF1D19 /* CBORCoding */ = {
+			isa = XCSwiftPackageProductDependency;
+			package = 8864664D29E5684C004FE2BE /* XCRemoteSwiftPackageReference "CBORCoding" */;
+			productName = CBORCoding;
+		};
+		88E197CF29EDCD7D00BF1D19 /* SFSafeSymbols */ = {
+			isa = XCSwiftPackageProductDependency;
+			package = 8864665029E5939C004FE2BE /* XCRemoteSwiftPackageReference "SFSafeSymbols" */;
+			productName = SFSafeSymbols;
+		};
 		E24EE77627FF95C00011CFD2 /* NIOCore */ = {
 			isa = XCSwiftPackageProductDependency;
 			package = E24EE77527FF95C00011CFD2 /* XCRemoteSwiftPackageReference "swift-nio" */;

Sesame.xcodeproj/xcuserdata/imac.xcuserdatad/xcschemes/xcschememanagement.plist

@@ -4,11 +4,16 @@
 <dict>
 	<key>SchemeUserState</key>
 	<dict>
-		<key>Sesame.xcscheme_^#shared#^_</key>
+		<key>Sesame-Watch Watch App.xcscheme_^#shared#^_</key>
 		<dict>
 			<key>orderHint</key>
 			<integer>0</integer>
 		</dict>
+		<key>Sesame.xcscheme_^#shared#^_</key>
+		<dict>
+			<key>orderHint</key>
+			<integer>1</integer>
+		</dict>
 	</dict>
 </dict>
 </plist>

Sesame/SymmetricKey+Extensions.swift

@@ -46,3 +46,26 @@ extension String {
         return results.map { String($0) }
     }
 }
+
+let protocolSalt = "CryptoKit Playgrounds Putting It Together".data(using: .utf8)!
+
+/// Generates an ephemeral key agreement key and performs key agreement to get the shared secret and derive the symmetric encryption key.
+func encrypt(_ data: Data, to theirEncryptionKey: Curve25519.KeyAgreement.PublicKey, signedBy ourSigningKey: Curve25519.Signing.PrivateKey) throws ->
+    (ephemeralPublicKeyData: Data, ciphertext: Data, signature: Data) {
+        let ephemeralKey = Curve25519.KeyAgreement.PrivateKey()
+        let ephemeralPublicKey = ephemeralKey.publicKey.rawRepresentation
+        
+        let sharedSecret = try ephemeralKey.sharedSecretFromKeyAgreement(with: theirEncryptionKey)
+        
+        let symmetricKey = sharedSecret.hkdfDerivedSymmetricKey(using: SHA256.self,
+                                                                salt: protocolSalt,
+                                                                sharedInfo: ephemeralPublicKey +
+                                                                    theirEncryptionKey.rawRepresentation +
+                                                                    ourSigningKey.publicKey.rawRepresentation,
+                                                                outputByteCount: 32)
+        
+        let ciphertext = try ChaChaPoly.seal(data, using: symmetricKey).combined
+        let signature = try ourSigningKey.signature(for: ciphertext + ephemeralPublicKey + theirEncryptionKey.rawRepresentation)
+        
+        return (ephemeralPublicKey, ciphertext, signature)
+}