Proper serialization and cleanup

Sesame.xcodeproj/project.pbxproj

@@ -20,8 +20,8 @@
 		E24EE77427FF95920011CFD2 /* DeviceResponse.swift in Sources */ = {isa = PBXBuildFile; fileRef = E24EE77327FF95920011CFD2 /* DeviceResponse.swift */; };
 		E24EE77727FF95C00011CFD2 /* NIOCore in Frameworks */ = {isa = PBXBuildFile; productRef = E24EE77627FF95C00011CFD2 /* NIOCore */; };
 		E24EE77927FF95E00011CFD2 /* Message.swift in Sources */ = {isa = PBXBuildFile; fileRef = E24EE77827FF95E00011CFD2 /* Message.swift */; };
-		E24EE77B280058240011CFD2 /* Message+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = E24EE77A280058240011CFD2 /* Message+Extensions.swift */; };
 		E2C5C1DB2806FE8900769EF6 /* RouteAPI.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2C5C1DA2806FE8900769EF6 /* RouteAPI.swift */; };
+		E2C5C1DD281B3AC400769EF6 /* UInt32+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = E2C5C1DC281B3AC400769EF6 /* UInt32+Extensions.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -38,8 +38,8 @@
 		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>"; };
-		E24EE77A280058240011CFD2 /* Message+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Message+Extensions.swift"; sourceTree = "<group>"; };
 		E2C5C1DA2806FE8900769EF6 /* RouteAPI.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RouteAPI.swift; sourceTree = "<group>"; };
+		E2C5C1DC281B3AC400769EF6 /* UInt32+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "UInt32+Extensions.swift"; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -102,7 +102,7 @@
 				E24EE77827FF95E00011CFD2 /* Message.swift */,
 				884A45CE27A5402D00D6E650 /* MessageResult.swift */,
 				E2C5C1DA2806FE8900769EF6 /* RouteAPI.swift */,
-				E24EE77A280058240011CFD2 /* Message+Extensions.swift */,
+				E2C5C1DC281B3AC400769EF6 /* UInt32+Extensions.swift */,
 			);
 			path = API;
 			sourceTree = "<group>";
@@ -186,8 +186,8 @@
 				884A45CF27A5402D00D6E650 /* MessageResult.swift in Sources */,
 				884A45B9279F48C100D6E650 /* ContentView.swift in Sources */,
 				E2C5C1DB2806FE8900769EF6 /* RouteAPI.swift in Sources */,
+				E2C5C1DD281B3AC400769EF6 /* UInt32+Extensions.swift in Sources */,
 				884A45CD27A465F500D6E650 /* Client.swift in Sources */,
-				E24EE77B280058240011CFD2 /* Message+Extensions.swift in Sources */,
 				E24EE77227FDCCC00011CFD2 /* Data+Extensions.swift in Sources */,
 				E24EE77427FF95920011CFD2 /* DeviceResponse.swift in Sources */,
 				884A45CB27A464C000D6E650 /* SymmetricKey+Extensions.swift in Sources */,

Sesame/API/Message+Extensions.swift

@@ -1,38 +0,0 @@
-import Foundation
-
-#if canImport(CryptoKit)
-import CryptoKit
-#else
-import Crypto
-#endif
-
-extension Message {
-
-    static var length: Int {
-        SHA256.byteCount + Content.length
-    }
-
-    init<T: Sequence>(decodeFrom data: T) where T.Element == UInt8 {
-        let count = SHA256.byteCount
-        self.mac = Data(data.prefix(count))
-        self.content = .init(decodeFrom: Array(data.dropFirst(count)))
-    }
-
-    func isValid(using key: SymmetricKey) -> Bool {
-         HMAC<SHA256>.isValidAuthenticationCode(mac, authenticating: content.encoded, using: key)
-    }
-}
-
-extension Message.Content {
-
-    func authenticate(using key: SymmetricKey) -> Message {
-        let mac = HMAC<SHA256>.authenticationCode(for: encoded, using: key)
-        return .init(mac: Data(mac.map { $0 }), content: self)
-    }
-
-    func authenticateAndSerialize(using key: SymmetricKey) -> Data {
-        let encoded = self.encoded
-        let mac = HMAC<SHA256>.authenticationCode(for: encoded, using: key)
-        return Data(mac.map { $0 }) + encoded
-    }
-}

Sesame/API/Message.swift

@@ -1,11 +1,36 @@
 import Foundation
 import NIOCore
 
+#if canImport(CryptoKit)
+import CryptoKit
+#else
+import Crypto
+#endif
+
 /**
  An authenticated message to or from the device.
  */
 struct Message: Equatable, Hashable {
 
+    /// The message authentication code for the message (32 bytes)
+    let mac: Data
+
+    /// The message content
+    let content: Content
+
+    /**
+     Create an authenticated message
+     - Parameter mac: The message authentication code
+     - Parameter content: The message content
+     */
+    init(mac: Data, content: Content) {
+        self.mac = mac
+        self.content = content
+    }
+}
+
+extension Message {
+
     /**
      The message content without authentication.
      */
@@ -30,13 +55,13 @@ struct Message: Equatable, Hashable {
         /**
          Decode message content from data.
 
-         The data consists of two `UInt32` encoded in big endian format (MSB at index 0)
+         The data consists of two `UInt32` encoded in little endian format
          - Warning: The sequence must contain at least 8 bytes, or the function will crash.
          - Parameter data: The sequence containing the bytes.
          */
         init<T: Sequence>(decodeFrom data: T) where T.Element == UInt8 {
-            self.time = UInt32(data: data.prefix(MemoryLayout<UInt32>.size))
+            self.time = UInt32(data: Data(data.prefix(MemoryLayout<UInt32>.size)))
-            self.id = UInt32(data: data.dropFirst(MemoryLayout<UInt32>.size))
+            self.id = UInt32(data: Data(data.dropFirst(MemoryLayout<UInt32>.size)))
         }
 
         /// The byte length of an encoded message content
@@ -48,27 +73,15 @@ struct Message: Equatable, Hashable {
         var encoded: Data {
             time.encoded + id.encoded
         }
-
-        /// The message content encoded to bytes
-        var bytes: [UInt8] {
-            time.bytes + id.bytes
-        }
     }
 
-    /// The message authentication code for the message (32 bytes)
+}
-    let mac: Data
 
-    /// The message content
+extension Message {
-    let content: Content
 
-    /**
+    /// The length of a message in bytes
-     Create an authenticated message
+    static var length: Int {
-     - Parameter mac: The message authentication code
+        SHA256.byteCount + Content.length
-     - Parameter content: The message content
-     */
-    init(mac: Data, content: Content) {
-        self.mac = mac
-        self.content = content
     }
 
     /**
@@ -88,35 +101,47 @@ struct Message: Equatable, Hashable {
         mac + content.encoded
     }
 
-    /// The message encoded to bytes
+    /**
-    var bytes: [UInt8] {
+     Create a message from received bytes.
-        Array(mac) + content.bytes
+     - Parameter data: The sequence of bytes
+     - Note: The sequence must contain at least `Message.length` bytes, or the function will crash.
+     */
+    init<T: Sequence>(decodeFrom data: T) where T.Element == UInt8 {
+        let count = SHA256.byteCount
+        self.mac = Data(data.prefix(count))
+        self.content = .init(decodeFrom: Array(data.dropFirst(count)))
+    }
+
+    /**
+     Check if the message contains a valid authentication code
+     - Parameter key: The key used to sign the message.
+     - Returns: `true`, if the message is valid.
+     */
+    func isValid(using key: SymmetricKey) -> Bool {
+         HMAC<SHA256>.isValidAuthenticationCode(mac, authenticating: content.encoded, using: key)
     }
 }
 
- extension UInt32 {
+extension Message.Content {
 
-     /**
+    /**
-      Create a value from a big-endian data representation (MSB first)
+     Calculate an authentication code for the message content.
-      - Note: The data must contain exactly four bytes.
+     - Parameter key: The key to use to sign the content.
-      */
+     - Returns: The new message signed with the key.
-     init<T: Sequence>(data: T) where T.Element == UInt8 {
+     */
-        self = data
+    func authenticate(using key: SymmetricKey) -> Message {
-            .reversed()
+        let mac = HMAC<SHA256>.authenticationCode(for: encoded, using: key)
-            .enumerated()
+        return .init(mac: Data(mac.map { $0 }), content: self)
-            .map { UInt32($0.element) << ($0.offset * 8) }
+    }
-            .reduce(0, +)
-     }
 
-     /// The value encoded to a big-endian representation
+    /**
-     var encoded: Data {
+     Calculate an authentication code for the message content and convert everything to data.
-         .init(bytes)
+     - Parameter key: The key to use to sign the content.
-     }
+     - Returns: The new message signed with the key, serialized to bytes.
-
+     */
-     /// The value encoded to a big-endian byte array
+    func authenticateAndSerialize(using key: SymmetricKey) -> Data {
-     var bytes: [UInt8] {
+        let encoded = self.encoded
-         (0..<4).reversed().map {
+        let mac = HMAC<SHA256>.authenticationCode(for: encoded, using: key)
-             UInt8((self >> ($0*8)) & 0xFF)
+        return Data(mac.map { $0 }) + encoded
-         }
+    }
-     }
 }

Sesame/API/UInt32+Extensions.swift

@@ -0,0 +1,18 @@
+import Foundation
+
+extension UInt32 {
+
+    /**
+     Create a value from a little-endian data representation (MSB first)
+     - Note: The data must contain exactly four bytes.
+     */
+    init(data: Data) {
+        let value = data.convert(into: UInt32.zero)
+        self = CFSwapInt32LittleToHost(value)
+    }
+
+    /// The value encoded to a little-endian representation
+    var encoded: Data {
+        Data(from: CFSwapInt32HostToLittle(self))
+    }
+}

Sesame/Data+Extensions.swift

@@ -40,3 +40,20 @@ extension Data {
         }
     }
 }
+
+extension Data {
+
+
+    func convert<T>(into value: T) -> T {
+        withUnsafeBytes {
+            $0.baseAddress!.load(as: T.self)
+        }
+    }
+
+    init<T>(from value: T) {
+        var target = value
+        self = Swift.withUnsafeBytes(of: &target) {
+            Data($0)
+        }
+    }
+}