client/src/main/java/envoy/client/net/Client.java

@@ -151,10 +151,7 @@ public final class Client implements EventListener, Closeable {
 		checkOnline();
 		logger.log(Level.FINE, "Sending " + obj);
 		try {
-			SerializationUtils.writeBytesWithLength(
+			SerializationUtils.writeBytesWithLength(obj, socket.getOutputStream());
-				new AuthenticatedRequest<>(obj,
-					Context.getInstance().getLocalDB().getUser().getID()),
-				socket.getOutputStream());
 		} catch (final IOException e) {
 			throw new RuntimeException(e);
 		}

client/src/main/java/envoy/client/ui/controller/ChatScene.java

@@ -593,7 +593,7 @@ public final class ChatScene implements EventListener, Restorable {
 		// IsTyping#millisecondsActive
 		if (client.isOnline() && currentChat.getLastWritingEvent()
 			+ IsTyping.millisecondsActive <= System.currentTimeMillis()) {
-			client.send(new IsTyping(getChatID(), currentChat.getRecipient().getID()));
+			client.send(new IsTyping(currentChat.getRecipient().getID()));
 			currentChat.lastWritingEventWasNow();
 		}
 
@@ -607,19 +607,6 @@ public final class ChatScene implements EventListener, Restorable {
 			checkPostConditions(false);
 	}
 
-	/**
-	 * Returns the id that should be used to send things to the server: the id of 'our' {@link User}
-	 * if the recipient of that object is another User, else the id of the {@link Group} 'our' user
-	 * is sending to.
-	 *
-	 * @return an id that can be sent to the server
-	 * @since Envoy Client v0.2-beta
-	 */
-	private long getChatID() {
-		return currentChat.getRecipient() instanceof User ? client.getSender().getID()
-			: currentChat.getRecipient().getID();
-	}
-
 	/**
 	 * @param e the keys that have been pressed
 	 * @since Envoy Client v0.1-beta

client/src/main/java/envoy/client/ui/settings/UserSettingsPane.java

@@ -137,7 +137,7 @@ public final class UserSettingsPane extends OnlineOnlySettingsPane {
 
 		// Displaying the save button
 		saveButton
-			.setOnAction(e -> save(client.getSender().getID(), currentPasswordField.getText()));
+			.setOnAction(e -> save(currentPasswordField.getText()));
 		saveButton.setAlignment(Pos.BOTTOM_RIGHT);
 		getChildren().add(saveButton);
 	}
@@ -148,11 +148,11 @@ public final class UserSettingsPane extends OnlineOnlySettingsPane {
 	 * @param username the new username
 	 * @since Envoy Client v0.2-beta
 	 */
-	private void save(long userID, String oldPassword) {
+	private void save(String oldPassword) {
 
 		// The profile pic was changed
 		if (profilePicChanged) {
-			final var profilePicChangeEvent = new ProfilePicChange(currentImageBytes, userID);
+			final var profilePicChangeEvent = new ProfilePicChange(currentImageBytes);
 			eventBus.dispatch(profilePicChangeEvent);
 			client.send(profilePicChangeEvent);
 			logger.log(Level.INFO, "The user just changed his profile pic.");
@@ -161,7 +161,7 @@ public final class UserSettingsPane extends OnlineOnlySettingsPane {
 		// The username was changed
 		final var validContactName = Bounds.isValidContactName(newUsername);
 		if (usernameChanged && validContactName) {
-			final var nameChangeEvent = new NameChange(userID, newUsername);
+			final var nameChangeEvent = new NameChange(client.getSender().getID(), newUsername);
 			eventBus.dispatch(nameChangeEvent);
 			client.send(nameChangeEvent);
 			logger.log(Level.INFO, "The user just changed his name to " + newUsername + ".");
@@ -178,7 +178,7 @@ public final class UserSettingsPane extends OnlineOnlySettingsPane {
 
 		// The password was changed
 		if (validPassword) {
-			client.send(new PasswordChangeRequest(newPassword, oldPassword, userID));
+			client.send(new PasswordChangeRequest(newPassword, oldPassword));
 			logger.log(Level.INFO, "The user just tried to change his password!");
 		} else if (!(validPassword || newPassword.isBlank())) {
 			final var alert = new Alert(AlertType.ERROR);

common/src/main/java/envoy/data/AuthenticatedRequest.java

@@ -1,61 +0,0 @@
-package envoy.data;
-
-import java.io.Serializable;
-import java.util.Objects;
-
-/**
- * Enables checking for the server whether the client is really who he is supposed to be.
- *
- * @author Leon Hofmeister
- * @param <T> the type of object to be sent
- * @since Envoy Common v0.3-beta
- */
-public final class AuthenticatedRequest<T extends Serializable> implements Serializable {
-
-	private final T		request;
-	private final long	userID;
-
-	private static final long serialVersionUID = 1L;
-
-	/**
-	 * @param request the actual object that should be sent
-	 * @param userID  the ID of the currently logged in user
-	 * @since Envoy Common v0.3-beta
-	 */
-	public AuthenticatedRequest(T request, long userID) {
-		this.request	= Objects.requireNonNull(request);
-		this.userID		= userID;
-	}
-
-	/**
-	 * @return the request
-	 * @since Envoy Common v0.3-beta
-	 */
-	public T getRequest() { return request; }
-
-	/**
-	 * @return the userID
-	 * @since Envoy Common v0.3-beta
-	 */
-	public long getUserID() { return userID; }
-
-	@Override
-	public int hashCode() {
-		return Objects.hash(request, userID);
-	}
-
-	@Override
-	public boolean equals(Object obj) {
-		if (this == obj)
-			return true;
-		if (!(obj instanceof AuthenticatedRequest))
-			return false;
-		AuthenticatedRequest<?> other = (AuthenticatedRequest<?>) obj;
-		return userID == other.userID;
-	}
-
-	@Override
-	public String toString() {
-		return "AuthenticatedRequest [request=" + request + ", userID=" + userID + "]";
-	}
-}

common/src/main/java/envoy/event/GroupMessageStatusChange.java

@@ -30,7 +30,7 @@ public final class GroupMessageStatusChange extends MessageStatusChange {
 	}
 
 	/**
-	 * @return the memberID which the user who sends this event has
+	 * @return the ID of the sender of this event
 	 * @since Envoy Common v0.1-beta
 	 */
 	public long getMemberID() { return memberID; }

common/src/main/java/envoy/event/IsTyping.java

@@ -8,8 +8,6 @@ package envoy.event;
  */
 public final class IsTyping extends Event<Long> {
 
-	private final long destinationID;
-
 	private static final long serialVersionUID = 1L;
 
 	/**
@@ -22,20 +20,13 @@ public final class IsTyping extends Event<Long> {
 	public static final int millisecondsActive = 3500;
 
 	/**
-	 * Creates a new {@code IsTyping} event with originator and recipient.
+	 * Creates a new {@code IsTyping}. The client will only send the contact that should receive
+	 * this event. The server will send the id of the contact who sent this event.
 	 *
-	 * @param sourceID      the ID of the originator
+	 * @param id the ID of the recipient (client)/ originator(server)
-	 * @param destinationID the ID of the contact the user wrote to
 	 * @since Envoy Common v0.2-beta
 	 */
-	public IsTyping(long sourceID, long destinationID) {
+	public IsTyping(long id) {
-		super(sourceID);
+		super(id);
-		this.destinationID = destinationID;
 	}
-
-	/**
-	 * @return the ID of the contact in whose chat the user typed something
-	 * @since Envoy Common v0.2-beta
-	 */
-	public long getDestinationID() { return destinationID; }
 }

common/src/main/java/envoy/event/PasswordChangeRequest.java

@@ -2,15 +2,12 @@ package envoy.event;
 
 import java.util.Objects;
 
-import envoy.data.Contact;
-
 /**
  * @author Leon Hofmeister
  * @since Envoy Common v0.2-beta
  */
 public final class PasswordChangeRequest extends Event<String> {
 
-	private final long		id;
 	private final String oldPassword;
 
 	private static final long serialVersionUID = 0L;
@@ -18,21 +15,13 @@ public final class PasswordChangeRequest extends Event<String> {
 	/**
 	 * @param newPassword the new password of that user
 	 * @param oldPassword the old password of that user
-	 * @param userID      the ID of the user who wants to change his password
 	 * @since Envoy Common v0.2-beta
 	 */
-	public PasswordChangeRequest(String newPassword, String oldPassword, long userID) {
+	public PasswordChangeRequest(String newPassword, String oldPassword) {
 		super(newPassword);
 		this.oldPassword = Objects.requireNonNull(oldPassword);
-		id					= userID;
 	}
 
-	/**
-	 * @return the ID of the {@link Contact} this event is related to
-	 * @since Envoy Common v0.2-alpha
-	 */
-	public long getID() { return id; }
-
 	/**
 	 * @return the old password of the underlying user
 	 * @since Envoy Common v0.2-beta
@@ -41,6 +30,6 @@ public final class PasswordChangeRequest extends Event<String> {
 
 	@Override
 	public String toString() {
-		return "PasswordChangeRequest[id=" + id + "]";
+		return "PasswordChangeRequest[]";
 	}
 }

common/src/main/java/envoy/event/ProfilePicChange.java

@@ -6,23 +6,13 @@ package envoy.event;
  */
 public final class ProfilePicChange extends Event<byte[]> {
 
-	private final long id;
-
 	private static final long serialVersionUID = 0L;
 
 	/**
 	 * @param value the byte[] of the new image
-	 * @param userID the ID of the user who changed his profile pic
 	 * @since Envoy Common v0.2-beta
 	 */
-	public ProfilePicChange(byte[] value, long userID) {
+	public ProfilePicChange(byte[] value) {
 		super(value);
-		id = userID;
 	}
-
-	/**
-	 * @return the ID of the user changing his profile pic
-	 * @since Envoy Common v0.2-beta
-	 */
-	public long getId() { return id; }
 }

server/src/main/java/envoy/server/net/ObjectMessageProcessor.java

@@ -7,10 +7,8 @@ import java.util.logging.*;
 
 import com.jenkov.nioserver.*;
 
-import envoy.data.AuthenticatedRequest;
 import envoy.util.EnvoyLog;
 
-import envoy.server.data.PersistenceManager;
 import envoy.server.processors.ObjectProcessor;
 
 /**
@@ -46,24 +44,9 @@ public final class ObjectMessageProcessor implements IMessageProcessor {
 				return;
 			}
 
-			// authenticate requests if necessary
+			logger.log(Level.INFO, "Received " + obj);
-			boolean authenticated = false;
-			if (obj instanceof AuthenticatedRequest)
-				try {
-					authenticated = PersistenceManager
-						.getInstance().getUserByID(((AuthenticatedRequest<?>) obj).getUserID())
-						.getID() == ConnectionManager.getInstance()
-							.getUserIDBySocketID(message.socketId);
 
-					// Class cast exception and NullPointerException are valid here and signify a
+			refer(message.socketId, writeProxy, obj);
-					// failed authentication
-				} catch (ClassCastException | NullPointerException e) {} finally {
-					obj = ((AuthenticatedRequest<?>) obj).getRequest();
-				}
-			logger.log(Level.INFO,
-				"Received " + (authenticated ? "" : "un") + "authenticated " + obj);
-
-			refer(message.socketId, writeProxy, obj, authenticated);
 		} catch (IOException | ClassNotFoundException e) {
 			logger.log(Level.WARNING,
 				"An exception occurred when reading in an object: " + e);
@@ -75,20 +58,14 @@ public final class ObjectMessageProcessor implements IMessageProcessor {
 	 * present.
 	 */
 	@SuppressWarnings("unchecked")
-	private void refer(long socketID, WriteProxy writeProxy, Object obj, boolean authenticated) {
+	private void refer(long socketID, WriteProxy writeProxy, Object obj) {
 
 		// Get processor and input class and process object
 		for (@SuppressWarnings("rawtypes")
 		ObjectProcessor p : processors) {
 			Class<?> c = (Class<?>) ((ParameterizedType) p.getClass().getGenericInterfaces()[0])
 				.getActualTypeArguments()[0];
-			if (c.equals(obj.getClass())) {
+			if (c.equals(obj.getClass()))
-				if (!authenticated && p.isAuthenticationRequired()) {
-					logger.log(Level.INFO,
-						"Discarding request as no authentication has been provided");
-					return;
-				}
-
 				try {
 					p.process(c.cast(obj), socketID, new ObjectWriteProxy(writeProxy));
 					break;
@@ -97,5 +74,4 @@ public final class ObjectMessageProcessor implements IMessageProcessor {
 				}
 		}
 	}
-	}
 }

server/src/main/java/envoy/server/processors/GroupMessageProcessor.java

@@ -5,7 +5,7 @@ import static envoy.server.Startup.config;
 
 import java.time.Instant;
 import java.util.Collections;
-import java.util.logging.Logger;
+import java.util.logging.*;
 
 import javax.persistence.EntityExistsException;
 
@@ -15,6 +15,7 @@ import envoy.util.EnvoyLog;
 
 import envoy.server.data.PersistenceManager;
 import envoy.server.net.*;
+import envoy.server.util.UserAuthenticationUtil;
 
 /**
  * @author Maximilian Käfer
@@ -29,6 +30,15 @@ public final class GroupMessageProcessor implements ObjectProcessor<GroupMessage
 
 	@Override
 	public void process(GroupMessage groupMessage, long socketID, ObjectWriteProxy writeProxy) {
+
+		// Check whether the message has the expected parameters
+		if (!UserAuthenticationUtil.isExpectedUser(groupMessage.getSenderID(), socketID)
+			|| persistenceManager.getContactByID(groupMessage.getRecipientID()) == null) {
+			logger.log(Level.INFO,
+				"Received a group message with invalid parameters");
+			return;
+		}
+
 		groupMessage.nextStatus();
 
 		// Update statuses to SENT / RECEIVED depending on online status

server/src/main/java/envoy/server/processors/GroupMessageStatusChangeProcessor.java

@@ -12,6 +12,7 @@ import envoy.util.EnvoyLog;
 
 import envoy.server.data.*;
 import envoy.server.net.*;
+import envoy.server.util.UserAuthenticationUtil;
 
 /**
  * @author Maximilian Käfer
@@ -28,6 +29,14 @@ public final class GroupMessageStatusChangeProcessor
 	@Override
 	public void process(GroupMessageStatusChange statusChange, long socketID,
 		ObjectWriteProxy writeProxy) {
+
+		// Check whether the message has the expected parameters
+		if (!UserAuthenticationUtil.isExpectedUser(statusChange.getMemberID(), socketID)) {
+			logger.log(Level.INFO,
+				"Received a group message with invalid parameters");
+			return;
+		}
+		
 		GroupMessage gmsg = (GroupMessage) persistenceManager.getMessageByID(statusChange.getID());
 
 		// Any other status than READ is not supposed to be sent to the server

server/src/main/java/envoy/server/processors/IsTypingProcessor.java

@@ -23,10 +23,11 @@ public final class IsTypingProcessor implements ObjectProcessor<IsTyping> {
 		throws IOException {
 		final var contact = persistenceManager.getContactByID(event.get());
 		if (contact instanceof User) {
-			final var destinationID = event.getDestinationID();
+			if (connectionManager.isOnline(event.get()))
-			if (connectionManager.isOnline(destinationID))
+				writeProxy.write(connectionManager.getSocketID(event.get()),
-				writeProxy.write(connectionManager.getSocketID(destinationID), event);
+					new IsTyping(connectionManager.getUserIDBySocketID(socketID)));
 		} else
-			writeProxy.writeToOnlineContacts(contact.getContacts(), event);
+			writeProxy.writeToOnlineContacts(contact.getContacts(),
+				new IsTyping(connectionManager.getUserIDBySocketID(socketID)));
 	}
 }

server/src/main/java/envoy/server/processors/IssueProposalProcessor.java

@@ -22,9 +22,6 @@ public final class IssueProposalProcessor implements ObjectProcessor<IssuePropos
 
 	private static final Logger logger = EnvoyLog.getLogger(IssueProposalProcessor.class);
 
-	@Override
-	public boolean isAuthenticationRequired() { return false; }
-
 	@Override
 	public void process(IssueProposal issueProposal, long socketID, ObjectWriteProxy writeProxy)
 		throws IOException {

server/src/main/java/envoy/server/processors/LoginCredentialProcessor.java

@@ -34,9 +34,6 @@ public final class LoginCredentialProcessor implements ObjectProcessor<LoginCred
 
 	private static final Logger logger = EnvoyLog.getLogger(LoginCredentialProcessor.class);
 
-	@Override
-	public boolean isAuthenticationRequired() { return false; }
-
 	@Override
 	public void process(LoginCredentials credentials, long socketID, ObjectWriteProxy writeProxy) {
 

server/src/main/java/envoy/server/processors/MessageProcessor.java

@@ -12,6 +12,7 @@ import envoy.util.EnvoyLog;
 
 import envoy.server.data.PersistenceManager;
 import envoy.server.net.*;
+import envoy.server.util.UserAuthenticationUtil;
 
 /**
  * This {@link ObjectProcessor} handles incoming {@link Message}s.
@@ -29,6 +30,15 @@ public final class MessageProcessor implements ObjectProcessor<Message> {
 
 	@Override
 	public void process(Message message, long socketID, ObjectWriteProxy writeProxy) {
+
+		// Check whether the message has the expected parameters
+		if (!UserAuthenticationUtil.isExpectedUser(message.getSenderID(), socketID)
+			|| persistenceManager.getContactByID(message.getRecipientID()) == null) {
+			logger.log(Level.INFO,
+				"Received a message with invalid parameters");
+			return;
+		}
+
 		message.nextStatus();
 
 		// Convert to server message

server/src/main/java/envoy/server/processors/ObjectProcessor.java

@@ -21,10 +21,4 @@ public interface ObjectProcessor<T> {
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
 	void process(T input, long socketID, ObjectWriteProxy writeProxy) throws IOException;
-
-	/**
-	 * @return whether authentication is required for the given processor. Defaults to {@code true}.
-	 * @since Envoy Server v0.3-beta
-	 */
-	default boolean isAuthenticationRequired() { return true; }
 }

server/src/main/java/envoy/server/processors/PasswordChangeRequestProcessor.java

@@ -7,7 +7,7 @@ import envoy.event.*;
 import envoy.util.EnvoyLog;
 
 import envoy.server.data.PersistenceManager;
-import envoy.server.net.ObjectWriteProxy;
+import envoy.server.net.*;
 import envoy.server.util.PasswordUtil;
 
 /**
@@ -21,7 +21,8 @@ public final class PasswordChangeRequestProcessor
 	public void process(PasswordChangeRequest event, long socketID, ObjectWriteProxy writeProxy)
 		throws IOException {
 		final var	persistenceManager		= PersistenceManager.getInstance();
-		final var	user					= persistenceManager.getUserByID(event.getID());
+		final var	user					= persistenceManager
+			.getUserByID(ConnectionManager.getInstance().getUserIDBySocketID(socketID));
 		final var	logger					=
 			EnvoyLog.getLogger(PasswordChangeRequestProcessor.class);
 		final var	correctAuthentication	=

server/src/main/java/envoy/server/util/UserAuthenticationUtil.java

@@ -0,0 +1,24 @@
+package envoy.server.util;
+
+import envoy.server.net.ConnectionManager;
+
+/**
+ * @author Leon Hofmeister
+ * @since Envoy Server v0.3-beta
+ */
+public final class UserAuthenticationUtil {
+
+	private UserAuthenticationUtil() {}
+
+	/**
+	 * Checks whether a user is really who he claims to be.
+	 *
+	 * @param expectedID the expected user ID
+	 * @param socketID   the socket ID of the user making a request
+	 * @return whether this user is who he claims to be
+	 * @since Envoy Server v0.3-beta
+	 */
+	public static boolean isExpectedUser(long expectedID, long socketID) {
+		return ConnectionManager.getInstance().getUserIDBySocketID(socketID) == expectedID;
+	}
+}