diff --git a/mobile/analysis_options.yaml b/mobile/analysis_options.yaml
index 018e17a..d5eb112 100644
--- a/mobile/analysis_options.yaml
+++ b/mobile/analysis_options.yaml
@@ -12,6 +12,14 @@ analyzer:
     invalid_return_type_for_catch_error: ignore
     use_build_context_synchronously: ignore
     use_null_aware_elements: ignore
+  exclude:
+    - build/**
+    - android/**
+    - ios/**
+    - web/**
+    - windows/**
+    - macos/**
+    - linux/**
 include: package:flutter_lints/flutter.yaml
 
 linter:
diff --git a/mobile/lib/controllers/auth_state.dart b/mobile/lib/controllers/auth_state.dart
index 54809cb..7bf2b26 100644
--- a/mobile/lib/controllers/auth_state.dart
+++ b/mobile/lib/controllers/auth_state.dart
@@ -2,6 +2,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'package:flutter/material.dart';
 import 'package:dio/dio.dart';
+import 'package:mobile/services/signal_service.dart';
 import 'package:url_launcher/url_launcher.dart';
 import 'package:app_links/app_links.dart';
 import 'package:mobile/models/user.dart';
@@ -67,13 +68,12 @@ class AuthState extends ChangeNotifier {
       final userData = data['data'] ?? data['user'] ?? data;
 
       _currentUser = UserModel.fromJson(userData);
-      
+
       await _authService.saveUserProfile(jsonEncode(userData));
       notifyListeners();
-      
     } catch (e) {
       debugPrint("Network failed, attempting to load cached user profile: $e");
-      
+
       try {
         final cachedData = await _authService.getCachedUserProfile();
         if (cachedData != null) {
@@ -81,8 +81,8 @@ class AuthState extends ChangeNotifier {
           _currentUser = UserModel.fromJson(decodedData);
           notifyListeners();
         } else {
-           _errorMessage = "No internet connection and no cached profile.";
-           notifyListeners();
+          _errorMessage = "No internet connection and no cached profile.";
+          notifyListeners();
         }
       } catch (cacheError) {
         debugPrint("Cache read failed: $cacheError");
@@ -95,6 +95,9 @@ class AuthState extends ChangeNotifier {
 
     if (_token != null) {
       await loadUserProfile();
+      if (_currentUser != null) {
+        await SignalService().initializeAndUploadKeys(_currentUser!.id);
+      }
     }
 
     notifyListeners();
@@ -129,6 +132,10 @@ class AuthState extends ChangeNotifier {
 
           await loadUserProfile();
 
+          if (_currentUser != null) {
+            await SignalService().initializeAndUploadKeys(_currentUser!.id);
+          }
+
           _isLoading = false;
           notifyListeners();
           return true;
@@ -179,6 +186,10 @@ class AuthState extends ChangeNotifier {
 
           await loadUserProfile();
 
+          if (_currentUser != null) {
+            await SignalService().initializeAndUploadKeys(_currentUser!.id);
+          }
+
           _isLoading = false;
           notifyListeners();
           return true;
@@ -237,6 +248,10 @@ class AuthState extends ChangeNotifier {
         await _authService.saveTokens(accessToken, refreshToken ?? accessToken);
         await loadUserProfile();
 
+        if (_currentUser != null) {
+          await SignalService().initializeAndUploadKeys(_currentUser!.id);
+        }
+
         _isLoading = false;
         notifyListeners();
         return true;
diff --git a/mobile/lib/controllers/chat/active_chat_controller.dart b/mobile/lib/controllers/chat/active_chat_controller.dart
index ef1e2d9..f51757c 100644
--- a/mobile/lib/controllers/chat/active_chat_controller.dart
+++ b/mobile/lib/controllers/chat/active_chat_controller.dart
@@ -1,5 +1,7 @@
 import 'dart:async';
+import 'dart:convert';
 import 'package:flutter/material.dart';
+import 'package:mobile/services/signal_service.dart';
 import 'package:sqflite_sqlcipher/sqflite.dart';
 import 'package:uuid/uuid.dart';
 import '../../models/message.dart';
@@ -40,7 +42,6 @@ class ActiveChatController extends ChangeNotifier {
     isPeerOnline = false;
     notifyListeners();
 
-    // 1. Load Local DB Messages
     try {
       final db = await DatabaseHelper.instance.database;
       final localData = await db.query(
@@ -78,15 +79,41 @@ class ActiveChatController extends ChangeNotifier {
       debugPrint("Local cache read failed: $e");
     }
 
-    // 2. Fetch Network History
     try {
       final res = await _api.getChatHistory(targetUid, isGroup: isGroup);
+
       if (currentChatUserId != targetUid) return;
 
       final targetList = _extractDataList(res.data, ['messages']);
-      final loadedMessages = targetList.reversed
-          .map((json) => Message.fromJson(json))
-          .toList();
+
+      final db = await DatabaseHelper.instance.database;
+      final localData = await db.query(
+        'messages',
+        where: 'chat_id = ?',
+        whereArgs: [targetUid],
+      );
+
+      final Map<String, String> localDecryptedContents = {};
+      for (var row in localData) {
+        final content = row['content'] as String;
+        if (!content.contains('ciphertext') && !content.contains('🔒')) {
+          localDecryptedContents[row['id'] as String] = content;
+        }
+      }
+
+      List<Message> loadedMessages = [];
+      for (var json in targetList.reversed) {
+        Message parsedMsg = Message.fromJson(json);
+
+        if (localDecryptedContents.containsKey(parsedMsg.id)) {
+          loadedMessages.add(
+            parsedMsg.copyWith(content: localDecryptedContents[parsedMsg.id]),
+          );
+        } else {
+          Message decryptedMsg = await _decryptMessageIfNeeded(parsedMsg);
+          loadedMessages.add(decryptedMsg);
+        }
+      }
 
       if (currentChatUserId != targetUid) return;
 
@@ -108,6 +135,10 @@ class ActiveChatController extends ChangeNotifier {
         final db = await DatabaseHelper.instance.database;
         Batch batch = db.batch();
         for (var msg in loadedMessages) {
+          if (msg.content.contains('ciphertext') || msg.content.contains('🔒')) {
+            continue; 
+          }
+
           batch.insert('messages', {
             'id': msg.id,
             'chat_id': targetUid,
@@ -148,9 +179,35 @@ class ActiveChatController extends ChangeNotifier {
       if (currentChatUserId != targetUid) return;
 
       final targetList = _extractDataList(res.data, ['messages']);
-      final loadedMessages = targetList.reversed
-          .map((json) => Message.fromJson(json))
-          .toList();
+
+      final db = await DatabaseHelper.instance.database;
+      final localData = await db.query(
+        'messages',
+        where: 'chat_id = ?',
+        whereArgs: [targetUid],
+      );
+
+      final Map<String, String> localDecryptedContents = {};
+      for (var row in localData) {
+        final content = row['content'] as String;
+        if (!content.contains('ciphertext') && !content.contains('🔒')) {
+          localDecryptedContents[row['id'] as String] = content;
+        }
+      }
+
+      List<Message> loadedMessages = [];
+      for (var json in targetList.reversed) {
+        Message parsedMsg = Message.fromJson(json);
+
+        if (localDecryptedContents.containsKey(parsedMsg.id)) {
+          loadedMessages.add(
+            parsedMsg.copyWith(content: localDecryptedContents[parsedMsg.id]),
+          );
+        } else {
+          Message decryptedMsg = await _decryptMessageIfNeeded(parsedMsg);
+          loadedMessages.add(decryptedMsg);
+        }
+      }
 
       if (currentChatUserId != targetUid) return;
 
@@ -196,6 +253,10 @@ class ActiveChatController extends ChangeNotifier {
           final db = await DatabaseHelper.instance.database;
           Batch batch = db.batch();
           for (var msg in loadedMessages) {
+            if (msg.content.contains('ciphertext') || msg.content.contains('🔒')) {
+              continue; 
+            }
+
             batch.insert('messages', {
               'id': msg.id,
               'chat_id': targetUid,
@@ -244,6 +305,15 @@ class ActiveChatController extends ChangeNotifier {
     if (currentChatUserId == null || cleanContent.isEmpty) return;
 
     final targetId = currentChatUserId!;
+
+    if (!isCurrentChatGroup) {
+      final sessionReady = await SignalService().establishSessionIfNeeded(targetId);
+      if (!sessionReady) {
+        debugPrint("Send aborted: Target user has no E2EE keys on server.");
+        return;
+      }
+    }
+
     final clientMessageId = _uuid.v4();
 
     QuotedMessage? quoted;
@@ -283,11 +353,28 @@ class ActiveChatController extends ChangeNotifier {
         'sync_status': 'pending',
       });
 
+      String securePayload;
+      if (isCurrentChatGroup) {
+        securePayload = jsonEncode({
+          'type': 0,
+          'ciphertext': cleanContent,
+        });
+      } else {
+        final encryptedData = await SignalService().encryptMessage(
+          targetId,
+          cleanContent,
+        );
+        securePayload = jsonEncode({
+          'type': encryptedData['type'],
+          'ciphertext': encryptedData['ciphertext'],
+        });
+      }
+
       final payload = {
         'messageId': clientMessageId,
         'receiverId': isCurrentChatGroup ? null : targetId,
         'groupId': isCurrentChatGroup ? targetId : null,
-        'content': cleanContent,
+        'content': securePayload,
         'replyToMessageId': replyingTo?.id,
       };
 
@@ -297,25 +384,25 @@ class ActiveChatController extends ChangeNotifier {
         payload,
       );
 
-      isCurrentChatGroup && senderId != null
-          ? _ws.sendGroupChat(
-              messageId: clientMessageId,
-              groupId: targetId,
-              content: cleanContent,
-              senderId: senderId,
-              replyToMessageId: replyingTo?.id,
-            )
-          : _ws.sendChat(
-              messageId: clientMessageId,
-              receiverId: targetId,
-              content: cleanContent,
-              replyToMessageId: replyingTo?.id,
-            );
+      if (isCurrentChatGroup) {
+        _ws.sendGroupChat(
+          messageId: clientMessageId,
+          groupId: targetId,
+          content: securePayload,
+          replyToMessageId: replyingTo?.id,
+        );
+      } else {
+        _ws.sendChat(
+          messageId: clientMessageId,
+          receiverId: targetId,
+          content: securePayload,
+          replyToMessageId: replyingTo?.id,
+        );
+      }
 
       if (_ws.isConnected) {
         markMessageAsSynced(clientMessageId);
       }
-
     } catch (e) {
       debugPrint("Immediate send failed, message queued: $e");
     }
@@ -416,9 +503,11 @@ class ActiveChatController extends ChangeNotifier {
     }
   }
 
-  void addRealTimeMessage(Message newMsg) {
+  void addRealTimeMessage(Message incomingMsg) async {
     if (currentChatUserId == null) return;
 
+    Message newMsg = await _decryptMessageIfNeeded(incomingMsg);
+
     bool belongsToCurrentChat =
         (isCurrentChatGroup && newMsg.receiverId == currentChatUserId) ||
         (!isCurrentChatGroup &&
@@ -432,6 +521,21 @@ class ActiveChatController extends ChangeNotifier {
         activeChat = [...activeChat, newMsg];
         notifyListeners();
 
+        try {
+          await DatabaseHelper.instance.insertMessage({
+            'id': newMsg.id,
+            'chat_id': currentChatUserId,
+            'sender_id': newMsg.senderId,
+            'content': newMsg.content,
+            'created_at': newMsg.createdAt.millisecondsSinceEpoch,
+            'is_read': newMsg.isRead ? 1 : 0,
+            'reply_to_id': newMsg.replyToMessageId,
+            'sync_status': 'synced',
+          });
+        } catch (e) {
+          debugPrint("Failed to save incoming WS message to DB: $e");
+        }
+
         _ws.sendReadReceipt(
           receiverId: isCurrentChatGroup ? null : currentChatUserId,
           groupId: isCurrentChatGroup ? currentChatUserId : null,
@@ -443,4 +547,94 @@ class ActiveChatController extends ChangeNotifier {
       }
     }
   }
+
+  Future<Message> _decryptMessageIfNeeded(Message msg) async {
+    final content = msg.content.trim();
+
+    if (content.startsWith('{') && content.contains('ciphertext')) {
+      
+      bool isSelfChat = msg.senderId == msg.receiverId;
+      bool isSentByMe = isSelfChat || (!isCurrentChatGroup && msg.senderId != currentChatUserId) || msg.senderId == 'me';
+
+      if (isSentByMe) {
+        try {
+          final db = await DatabaseHelper.instance.database;
+          
+          final exactMatch = await db.query(
+            'messages',
+            where: 'id = ?',
+            whereArgs: [msg.id],
+          );
+
+          if (exactMatch.isNotEmpty) {
+            final exactContent = exactMatch.first['content'].toString();
+            if (!exactContent.contains('ciphertext') && !exactContent.contains('🔒')) {
+              return msg.copyWith(content: exactContent);
+            } 
+          } 
+
+          final targetChatId = currentChatUserId ?? msg.receiverId;
+          final fallbackRows = await db.query(
+            'messages',
+            where: 'chat_id = ?',
+            whereArgs: [targetChatId],
+          );
+
+          int minDiff = -1;
+          String? closestPlaintext;
+
+          for (var row in fallbackRows) {
+            final rSender = row['sender_id'].toString();
+            if (rSender != 'me' && rSender != msg.senderId) continue;
+
+            final rowContent = row['content'].toString();
+            if (rowContent.contains('ciphertext') || rowContent.contains('🔒')) continue;
+
+            final localTime = row['created_at'] as int;
+            final diff = (localTime - msg.createdAt.millisecondsSinceEpoch).abs();
+
+            if (minDiff == -1 || diff < minDiff) {
+              minDiff = diff;
+              closestPlaintext = rowContent;
+            }
+          }
+
+          if (closestPlaintext != null) {
+            return msg.copyWith(content: closestPlaintext);
+          } 
+        } catch (e) {
+          debugPrint("Local sent-message lookup crashed: $e");
+        }
+        
+        return msg.copyWith(content: "🔒 [Sent from another device]");
+      }
+
+      try {
+        final Map<String, dynamic> payload = jsonDecode(content);
+
+        if (isCurrentChatGroup && payload['type'] == 0) {
+          return msg.copyWith(content: payload['ciphertext']);
+        }
+
+        final decryptedText = await SignalService().decryptMessage(
+          msg.senderId,
+          payload['ciphertext'],
+          payload['type'],
+        );
+        return msg.copyWith(content: decryptedText);
+      } catch (e) {
+        debugPrint("LibSignal Decryption Failed: $e");
+        final errStr = e.toString();
+
+        if (errStr.contains('DuplicateMessageException')) {
+          return msg.copyWith(content: "🔒 [Message already decrypted]");
+        } else if (errStr.contains('NoSessionException') || errStr.contains('Bad Mac')) {
+          return msg.copyWith(content: "🔒 [Encrypted for past session]");
+        }
+
+        return msg.copyWith(content: "🔒 [Encrypted Message]");
+      }
+    }
+    return msg;
+  }
 }
\ No newline at end of file
diff --git a/mobile/lib/controllers/chat/inbox_controller.dart b/mobile/lib/controllers/chat/inbox_controller.dart
index 593449e..bd8ec79 100644
--- a/mobile/lib/controllers/chat/inbox_controller.dart
+++ b/mobile/lib/controllers/chat/inbox_controller.dart
@@ -38,19 +38,40 @@ class InboxController extends ChangeNotifier {
     try {
       final response = await _api.getConversations();
       final rawData = _parseResponse(response.data, ['conversations']);
+      final db = await DatabaseHelper.instance.database;
 
       List<InboxItem> combinedInbox = [];
       for (var json in rawData) {
         try {
           final bool isGroup =
               json['is_group'] == true || json['type'] == 'group';
+
+          InboxItem item;
           if (isGroup) {
-            combinedInbox.add(InboxItem.fromGroup(Group.fromJson(json)));
+            item = InboxItem.fromGroup(Group.fromJson(json));
           } else {
-            combinedInbox.add(
-              InboxItem.fromConversation(Conversation.fromJson(json)),
+            item = InboxItem.fromConversation(Conversation.fromJson(json));
+          }
+
+          if (item.lastMessage.contains('ciphertext') ||
+              item.lastMessage.contains('🔒')) {
+            final localMsg = await db.query(
+              'messages',
+              where:
+                  'chat_id = ? AND content NOT LIKE ? AND content NOT LIKE ?',
+              whereArgs: [item.id, '%ciphertext%', '%🔒%'],
+              orderBy: 'created_at DESC',
+              limit: 1,
             );
+
+            if (localMsg.isNotEmpty) {
+              item.lastMessage = localMsg.first['content'].toString();
+            } else {
+              item.lastMessage = "🔒 Encrypted Message";
+            }
           }
+
+          combinedInbox.add(item);
         } catch (e) {
           debugPrint("BAD JSON OBJECT: $json");
         }
@@ -162,6 +183,10 @@ class InboxController extends ChangeNotifier {
       final db = await DatabaseHelper.instance.database;
       Batch batch = db.batch();
       for (var msg in loadedMessages) {
+        if (msg.content.contains('ciphertext') || msg.content.contains('🔒')) {
+          continue;
+        }
+
         batch.insert('messages', {
           'id': msg.id,
           'chat_id': chatId,
diff --git a/mobile/lib/models/message.dart b/mobile/lib/models/message.dart
index 8f553d5..9be807d 100644
--- a/mobile/lib/models/message.dart
+++ b/mobile/lib/models/message.dart
@@ -108,12 +108,13 @@ class Message {
     bool? isRead,
     String? id,
     String? syncStatus,
+    String? content,
   }) {
     return Message(
       id: id ?? this.id,
       senderId: senderId,
       receiverId: receiverId,
-      content: content,
+      content: content ?? this.content,
       createdAt: createdAt,
       isRead: isRead ?? this.isRead,
       replyToMessageId: replyToMessageId,
diff --git a/mobile/lib/pages/chat/chat_details_page.dart b/mobile/lib/pages/chat/chat_details_page.dart
index bfaa77c..2f0392e 100644
--- a/mobile/lib/pages/chat/chat_details_page.dart
+++ b/mobile/lib/pages/chat/chat_details_page.dart
@@ -8,7 +8,9 @@ import 'package:mobile/controllers/chat/group_details_controller.dart';
 import 'package:mobile/controllers/chat/inbox_controller.dart';
 import 'package:mobile/pages/chat/chat_page.dart';
 import 'package:mobile/providers/group_controller_provider.dart';
+import 'package:mobile/services/signal_service.dart';
 import 'package:provider/provider.dart';
+import 'package:qr_flutter/qr_flutter.dart';
 
 class ChatMember {
   final String userId;
@@ -181,9 +183,88 @@ class _ChatDetailsPageState extends State<ChatDetailsPage> {
             leading: const Icon(Icons.lock),
             title: const Text('Encryption'),
             subtitle: const Text(
-              'Messages and calls are end-to-end encrypted.',
+              'Messages and calls are end-to-end encrypted. Tap to verify.',
             ),
-            onTap: () {},
+            onTap: () async {
+              final currentUserId = context.read<AuthState>().currentUser?.id;
+              if (currentUserId == null) return;
+
+              final safetyNumber = await SignalService().getSafetyNumber(
+                currentUserId, 
+                widget.chatId
+              );
+
+              if (!context.mounted) return;
+
+              if (safetyNumber == null) {
+                ScaffoldMessenger.of(context).showSnackBar(
+                  const SnackBar(content: Text('Send a message first to establish a secure session.')),
+                );
+                return;
+              }
+
+              showModalBottomSheet(
+                context: context,
+                isScrollControlled: true,
+                backgroundColor: Theme.of(context).scaffoldBackgroundColor,
+                shape: const RoundedRectangleBorder(
+                  borderRadius: BorderRadius.vertical(top: Radius.circular(20)),
+                ),
+                builder: (context) => Padding(
+                  padding: const EdgeInsets.all(24.0),
+                  child: Column(
+                    mainAxisSize: MainAxisSize.min,
+                    children: [
+                      const Text(
+                        "Verify Security Code",
+                        style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
+                      ),
+                      const SizedBox(height: 20),
+                      Container(
+                        padding: const EdgeInsets.all(16),
+                        color: Colors.white,
+                        child: QrImageView(
+                          data: safetyNumber,
+                          version: QrVersions.auto,
+                          size: 200.0,
+                        ),
+                      ),
+                      const SizedBox(height: 20),
+                      Text(
+                        safetyNumber,
+                        textAlign: TextAlign.center,
+                        style: const TextStyle(
+                          fontSize: 16, 
+                          letterSpacing: 2, 
+                          fontWeight: FontWeight.w500
+                        ),
+                      ),
+                      const SizedBox(height: 20),
+                      const Text(
+                        "To verify that messages and calls are end-to-end encrypted, scan this code on your contact's phone, or compare the number above.",
+                        textAlign: TextAlign.center,
+                        style: TextStyle(color: Colors.grey),
+                      ),
+                      const SizedBox(height: 40),
+                    ],
+                  ),
+                ),
+              );
+            },
+          ),
+          const Divider(height: 1),
+          ListTile(
+            leading: const Icon(Icons.refresh, color: Colors.orange),
+            title: const Text('Reset Secure Session', style: TextStyle(color: Colors.orange)),
+            subtitle: const Text('Use this if messages are failing to decrypt.'),
+            onTap: () async {
+               await SignalService().forceResetSession(widget.chatId);
+               if (context.mounted) {
+                 ScaffoldMessenger.of(context).showSnackBar(
+                   const SnackBar(content: Text('Secure session reset. Send a new message to reconnect.')),
+                 );
+               }
+            },
           ),
           const Divider(height: 1),
           ListTile(
diff --git a/mobile/lib/pages/chat/chat_page.dart b/mobile/lib/pages/chat/chat_page.dart
index 112520a..5b89f9c 100644
--- a/mobile/lib/pages/chat/chat_page.dart
+++ b/mobile/lib/pages/chat/chat_page.dart
@@ -537,7 +537,7 @@ class _ChatPageState extends State<ChatPage> with WidgetsBindingObserver {
                           itemCount:
                               activeChat.length +
                               (chatState.isPeerTyping ? 2 : 1) +
-                              1,
+                              2,
                           itemBuilder: (context, index) {
                             if (index == 0) {
                               return const SizedBox(height: 140);
@@ -595,6 +595,33 @@ class _ChatPageState extends State<ChatPage> with WidgetsBindingObserver {
                                 index - (chatState.isPeerTyping ? 3 : 2);
                             final int realIndex =
                                 activeChat.length - 1 - msgIndex;
+                            if (realIndex == -1) {
+                              return Padding(
+                                padding: const EdgeInsets.symmetric(
+                                  vertical: 24.0,
+                                  horizontal: 16.0,
+                                ),
+                                child: Container(
+                                  padding: const EdgeInsets.all(12),
+                                  decoration: BoxDecoration(
+                                    color: theme
+                                        .colorScheme
+                                        .surfaceContainerHighest
+                                        .withValues(alpha: 0.5),
+                                    borderRadius: BorderRadius.circular(12),
+                                  ),
+                                  child: Text(
+                                    "🔒 Messages and calls are end-to-end encrypted. No one outside of this chat can read or listen to them.",
+                                    textAlign: TextAlign.center,
+                                    style: TextStyle(
+                                      fontSize: 12,
+                                      color: theme.colorScheme.primary,
+                                      fontWeight: FontWeight.w500,
+                                    ),
+                                  ),
+                                ),
+                              );
+                            }
                             final msg = activeChat[realIndex];
 
                             final bool isHighlighted =
diff --git a/mobile/lib/pages/settings/privacy_security.dart b/mobile/lib/pages/settings/privacy_security.dart
index d55c347..9a1ffec 100644
--- a/mobile/lib/pages/settings/privacy_security.dart
+++ b/mobile/lib/pages/settings/privacy_security.dart
@@ -1,10 +1,94 @@
 import 'package:flutter/material.dart';
+import 'package:mobile/services/signal_service.dart';
 
 class PrivacySecuritySettingsPage extends StatelessWidget {
   const PrivacySecuritySettingsPage({super.key});
 
   @override
   Widget build(BuildContext context) {
-    return Scaffold(appBar: AppBar(title: Text('Privacy and security')));
+    final theme = Theme.of(context);
+
+    return Scaffold(
+      appBar: AppBar(title: const Text('Privacy and security')),
+      body: ListView(
+        children: [
+          Padding(
+            padding: const EdgeInsets.all(24.0),
+            child: Column(
+              children: [
+                Icon(
+                  Icons.lock_person,
+                  size: 64,
+                  color: theme.colorScheme.primary,
+                ),
+                const SizedBox(height: 16),
+                const Text(
+                  "Your privacy is protected",
+                  style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
+                ),
+                const SizedBox(height: 8),
+                Text(
+                  "Elephant uses the Signal Protocol to secure your messages. Nobody, not even Elephant, can read your messages or listen to your calls.",
+                  textAlign: TextAlign.center,
+                  style: TextStyle(color: theme.colorScheme.onSurfaceVariant),
+                ),
+              ],
+            ),
+          ),
+          const Divider(),
+          const ListTile(
+            leading: Icon(Icons.timer),
+            title: Text('Disappearing messages'),
+            subtitle: Text('Off'),
+            trailing: Icon(Icons.chevron_right),
+          ),
+          const Divider(),
+          ListTile(
+            leading: const Icon(Icons.delete_forever, color: Colors.red),
+            title: const Text(
+              'Reset All Secure Sessions',
+              style: TextStyle(color: Colors.red),
+            ),
+            subtitle: const Text('Fixes widespread decryption errors.'),
+            onTap: () {
+              showDialog(
+                context: context,
+                builder: (context) => AlertDialog(
+                  title: const Text("Reset All Sessions?"),
+                  content: const Text(
+                    "This will delete all local cryptographic sessions. Your chat history will remain, but you will need to exchange new messages to re-establish secure connections with your contacts.",
+                  ),
+                  actions: [
+                    TextButton(
+                      onPressed: () => Navigator.pop(context),
+                      child: const Text("Cancel"),
+                    ),
+                    TextButton(
+                      onPressed: () async {
+                        Navigator.pop(context);
+                        await SignalService().clearAllSessions();
+                        if (context.mounted) {
+                          ScaffoldMessenger.of(context).showSnackBar(
+                            const SnackBar(
+                              content: Text(
+                                'All secure sessions have been reset.',
+                              ),
+                            ),
+                          );
+                        }
+                      },
+                      child: const Text(
+                        "Reset",
+                        style: TextStyle(color: Colors.red),
+                      ),
+                    ),
+                  ],
+                ),
+              );
+            },
+          ),
+        ],
+      ),
+    );
   }
 }
diff --git a/mobile/lib/services/chat/chat_event_handler.dart b/mobile/lib/services/chat/chat_event_handler.dart
index c9f0251..31b567e 100644
--- a/mobile/lib/services/chat/chat_event_handler.dart
+++ b/mobile/lib/services/chat/chat_event_handler.dart
@@ -1,4 +1,7 @@
+import 'dart:convert';
+
 import 'package:flutter/material.dart';
+import 'package:mobile/services/signal_service.dart';
 import 'package:sqflite_sqlcipher/sqflite.dart';
 import 'package:mobile/controllers/chat/active_chat_controller.dart';
 import 'package:mobile/controllers/chat/inbox_controller.dart';
@@ -35,11 +38,17 @@ class ChatEventHandler {
             .toLowerCase();
         isCurrentChat = (eventGroupId == cleanCurrentChat);
       } else {
-        final String? eventSenderId = data['sender_id']?.toString().trim().toLowerCase() ?? 
-                                      data['sender']?.toString().trim().toLowerCase();
-        final String? eventReceiverId = data['receiver_id']?.toString().trim().toLowerCase();
-        
-        isCurrentChat = (eventSenderId == cleanCurrentChat || eventReceiverId == cleanCurrentChat);
+        final String? eventSenderId =
+            data['sender_id']?.toString().trim().toLowerCase() ??
+            data['sender']?.toString().trim().toLowerCase();
+        final String? eventReceiverId = data['receiver_id']
+            ?.toString()
+            .trim()
+            .toLowerCase();
+
+        isCurrentChat =
+            (eventSenderId == cleanCurrentChat ||
+            eventReceiverId == cleanCurrentChat);
       }
     }
 
@@ -61,14 +70,21 @@ class ChatEventHandler {
       case 'chat':
       case 'message':
         final String? incomingId = data['id']?.toString();
-        final String echoId = data['message_id']?.toString() ??
+        final String echoId =
+            data['message_id']?.toString() ??
             data['messageId']?.toString() ??
             data['client_message_id']?.toString() ??
             incomingId ??
             '';
 
-        final String cleanSenderId = (data['sender_id'] ?? data['sender'] ?? '').toString().trim().toLowerCase();
-        final String cleanReceiverId = (data['receiver_id'] ?? '').toString().trim().toLowerCase();
+        final String cleanSenderId = (data['sender_id'] ?? data['sender'] ?? '')
+            .toString()
+            .trim()
+            .toLowerCase();
+        final String cleanReceiverId = (data['receiver_id'] ?? '')
+            .toString()
+            .trim()
+            .toLowerCase();
         final String myId = currentUserId.trim().toLowerCase();
         final bool isMe = (cleanSenderId == 'me' || cleanSenderId == myId);
 
@@ -76,6 +92,27 @@ class ChatEventHandler {
             ? data['group_id'].toString()
             : (isMe ? cleanReceiverId : cleanSenderId);
 
+        try {
+          final String rawContent = data['content']?.toString() ?? '';
+          if (rawContent.startsWith('{') && rawContent.contains('ciphertext')) {
+            final Map<String, dynamic> payload = jsonDecode(rawContent);
+            final String remoteSender = data['sender_id']?.toString() ?? '';
+
+            final decryptedText = await SignalService().decryptMessage(
+              remoteSender,
+              payload['ciphertext'],
+              payload['type'],
+            );
+            data['content'] =
+                decryptedText;
+          }
+        } catch (e) {
+          debugPrint(
+            "❌ Decryption failed for message. It may be out of sync: $e",
+          );
+          data['content'] = "🔒 [Message Decryption Failed]";
+        }
+
         try {
           final db = await DatabaseHelper.instance.database;
           final queuedItems = await db.query(
@@ -88,7 +125,7 @@ class ChatEventHandler {
 
           if (isOurMessage) {
             final String newMsgId = incomingId ?? echoId;
-            
+
             int index = activeChatController.activeChat.indexWhere(
               (m) => m.id == echoId || m.id == newMsgId,
             );
@@ -107,7 +144,9 @@ class ChatEventHandler {
             if (index != -1) {
               final existingMsg = activeChatController.activeChat[index];
 
-              final newList = List<Message>.from(activeChatController.activeChat);
+              final newList = List<Message>.from(
+                activeChatController.activeChat,
+              );
               newList[index] = Message(
                 id: newMsgId,
                 senderId: existingMsg.senderId,
@@ -123,11 +162,19 @@ class ChatEventHandler {
               activeChatController.activeChat = newList;
               activeChatController.refreshUI();
 
-              await db.delete('action_queue', where: 'id = ?', whereArgs: [originalClientId]);
+              await db.delete(
+                'action_queue',
+                where: 'id = ?',
+                whereArgs: [originalClientId],
+              );
               if (originalClientId != newMsgId) {
-                await db.delete('messages', where: 'id = ?', whereArgs: [originalClientId]);
+                await db.delete(
+                  'messages',
+                  where: 'id = ?',
+                  whereArgs: [originalClientId],
+                );
               }
-              
+
               await db.insert('messages', {
                 'id': newMsgId,
                 'chat_id': dbChatId,
@@ -173,7 +220,9 @@ class ChatEventHandler {
           }, conflictAlgorithm: ConflictAlgorithm.replace);
 
           if (isCurrentChat) {
-            if (!activeChatController.activeChat.any((msg) => msg.id == incomingMsg.id)) {
+            if (!activeChatController.activeChat.any(
+              (msg) => msg.id == incomingMsg.id,
+            )) {
               activeChatController.activeChat = [
                 ...activeChatController.activeChat,
                 incomingMsg,
@@ -199,7 +248,6 @@ class ChatEventHandler {
             syncStatus: 'synced',
             isRead: isCurrentChat,
           );
-
         } catch (e) {
           debugPrint("Failed to save incoming message to DB: $e");
         }
@@ -217,10 +265,17 @@ class ChatEventHandler {
         break;
 
       case 'read_receipt':
-        final String payloadSender = (data['sender_id'] ?? '').toString().toLowerCase();
-        final String payloadReceiver = (data['receiver_id'] ?? '').toString().toLowerCase();
-        final String payloadGroup = (data['group_id'] ?? '').toString().toLowerCase();
-        final String safeChatId = (activeChatController.currentChatUserId ?? '').toLowerCase();
+        final String payloadSender = (data['sender_id'] ?? '')
+            .toString()
+            .toLowerCase();
+        final String payloadReceiver = (data['receiver_id'] ?? '')
+            .toString()
+            .toLowerCase();
+        final String payloadGroup = (data['group_id'] ?? '')
+            .toString()
+            .toLowerCase();
+        final String safeChatId = (activeChatController.currentChatUserId ?? '')
+            .toLowerCase();
 
         bool isRelevantToThisChat = false;
         String dbTargetChatId = "";
@@ -283,4 +338,4 @@ class ChatEventHandler {
         break;
     }
   }
-}
\ No newline at end of file
+}
diff --git a/mobile/lib/services/chat/chat_sync_service.dart b/mobile/lib/services/chat/chat_sync_service.dart
index 89a8d41..08c26a4 100644
--- a/mobile/lib/services/chat/chat_sync_service.dart
+++ b/mobile/lib/services/chat/chat_sync_service.dart
@@ -31,7 +31,7 @@ class ChatSyncService {
                 messageId: payload['messageId'],
                 groupId: payload['groupId'],
                 content: payload['content'],
-                senderId: currentUserId.isNotEmpty ? currentUserId : 'me',
+                // senderId: currentUserId.isNotEmpty ? currentUserId : 'me',
                 replyToMessageId: payload['replyToMessageId'],
               );
             } else {
diff --git a/mobile/lib/services/db_services.dart b/mobile/lib/services/db_services.dart
index 85424a7..fabd74e 100644
--- a/mobile/lib/services/db_services.dart
+++ b/mobile/lib/services/db_services.dart
@@ -89,17 +89,73 @@ class DatabaseHelper {
         PRIMARY KEY (group_id, user_id)
       )
     ''');
+
+    await db.execute('''
+      CREATE TABLE signal_local_keys (
+        id INTEGER PRIMARY KEY DEFAULT 1,
+        registration_id INTEGER NOT NULL,
+        identity_key_pair TEXT NOT NULL
+      )
+    ''');
+
+    await db.execute('''
+      CREATE TABLE signal_identities (
+        address TEXT PRIMARY KEY,
+        identity_key TEXT NOT NULL
+      )
+    ''');
+
+    await db.execute('''
+      CREATE TABLE signal_sessions (
+        address TEXT PRIMARY KEY,
+        record TEXT NOT NULL
+      )
+    ''');
+
+    await db.execute('''
+      CREATE TABLE signal_prekeys (
+        key_id INTEGER PRIMARY KEY,
+        record TEXT NOT NULL
+      )
+    ''');
+
+    await db.execute('''
+      CREATE TABLE signal_signed_prekeys (
+        key_id INTEGER PRIMARY KEY,
+        record TEXT NOT NULL
+      )
+    ''');
   }
 
-  Future<void> insertMessage(Map<String, dynamic> messageData) async {
-    final db = await instance.database;
-    await db.insert(
-      'messages',
-      messageData,
+  Future<int> insertMessage(Map<String, dynamic> row) async {
+    Database db = await instance.database;
+
+    if (row['content'] != null) {
+      String newContent = row['content'].toString();
+      
+      if (newContent.contains('ciphertext') || newContent.contains('🔒')) {
+        List<Map<String, dynamic>> existing = await db.query(
+          'messages', 
+          where: 'id = ?', 
+          whereArgs: [row['id']],
+        );
+
+        if (existing.isNotEmpty) {
+          String oldContent = existing.first['content'].toString();
+          if (!oldContent.contains('ciphertext') && !oldContent.contains('🔒')) {
+            row['content'] = oldContent; 
+          }
+        }
+      }
+    }
+
+    return await db.insert(
+      'messages', 
+      row, 
       conflictAlgorithm: ConflictAlgorithm.replace,
     );
   }
-
+  
   Future<void> queueAction(
     String id,
     String type,
diff --git a/mobile/lib/services/signal_service.dart b/mobile/lib/services/signal_service.dart
new file mode 100644
index 0000000..e29f39f
--- /dev/null
+++ b/mobile/lib/services/signal_service.dart
@@ -0,0 +1,223 @@
+import 'dart:convert';
+import 'dart:typed_data';
+import 'package:dio/dio.dart';
+import 'package:flutter/foundation.dart';
+import 'package:libsignal_protocol_dart/libsignal_protocol_dart.dart';
+import 'package:mobile/services/sqlite_signal_store.dart';
+import 'package:mobile/services/db_services.dart';
+import 'api_services.dart';
+
+class SignalService {
+  static final SignalService _instance = SignalService._internal();
+  factory SignalService() => _instance;
+
+  final ApiService _api = ApiService();
+
+  late SQLiteSignalStore _store;
+  bool _isInitialized = false;
+
+  SignalService._internal();
+
+  Future<void> initStore() async {
+    if (_isInitialized) return;
+    _store = SQLiteSignalStore();
+    _isInitialized = true;
+  }
+
+  SignalProtocolAddress _getAddress(String userId) =>
+      SignalProtocolAddress(userId, 1);
+
+  Future<void> initializeAndUploadKeys(String currentUserId) async {
+    await initStore();
+
+    final db = await DatabaseHelper.instance.database;
+    final existingKeys = await db.query('signal_local_keys', where: 'id = 1');
+
+    if (existingKeys.isNotEmpty) {
+      debugPrint("E2EE: Keys already exist locally. Skipping generation.");
+      return;
+    }
+
+    debugPrint("E2EE: Generating new local identity keys...");
+
+    final identityKeyPair = generateIdentityKeyPair();
+    final registrationId = generateRegistrationId(false);
+
+    await _store.storeLocalData(identityKeyPair, registrationId);
+
+    final preKeys = generatePreKeys(0, 100);
+    final signedPreKey = generateSignedPreKey(identityKeyPair, 0);
+
+    for (var preKey in preKeys) {
+      await _store.storePreKey(preKey.id, preKey);
+    }
+    await _store.storeSignedPreKey(signedPreKey.id, signedPreKey);
+
+    final publicPreKeys = preKeys
+        .map(
+          (k) => {
+            'id': k.id, 
+            'content': base64Encode(k.getKeyPair().publicKey.serialize()), 
+          },
+        )
+        .toList();
+
+    final payload = {
+      'device_id': 'main', 
+      'identity_key': base64Encode(identityKeyPair.getPublicKey().serialize()),
+      'signed_prekey': base64Encode(signedPreKey.getKeyPair().publicKey.serialize()),
+      'signature': base64Encode(signedPreKey.signature),
+      'one_time_prekeys': publicPreKeys,
+    };
+
+    try {
+      await _api.post("/e2ee/keys", data: payload); 
+      debugPrint("E2EE Keys uploaded successfully");
+    } catch (e) {
+      debugPrint("Failed to upload E2EE keys: $e");
+    }
+  }
+
+  Future<bool> establishSessionIfNeeded(String remoteUserId) async {
+    await initStore();
+    final address = _getAddress(remoteUserId);
+
+    if (await _store.containsSession(address)) return true; 
+
+    try {
+      final response = await _api.get("/e2ee/bundle/$remoteUserId?device_id=main");
+      final data = response.data['data'] ?? response.data;
+
+      final identityKeyStr = data['identity_key'];
+      final signedPreKeyStr = data['signed_prekey'];
+      final signatureStr = data['signature'];
+      final otpBodyStr = data['one_time_prekey_body'];
+      final otpId = data['one_time_prekey_id'];
+
+      if (identityKeyStr == null || signedPreKeyStr == null || signatureStr == null || otpBodyStr == null) {
+        debugPrint("Receiver bundle is missing required cryptographic keys.");
+        return false;
+      }
+
+      final identityKey = IdentityKey(Curve.decodePoint(base64Decode(identityKeyStr), 0));
+      final signedPreKey = Curve.decodePoint(base64Decode(signedPreKeyStr), 0);
+      final signature = base64Decode(signatureStr);
+      final preKey = Curve.decodePoint(base64Decode(otpBodyStr), 0);
+
+      final bundle = PreKeyBundle(
+        0,                      
+        1,                      
+        (otpId as int?) ?? 1,   
+        preKey,                 
+        0,                      
+        signedPreKey,           
+        signature,              
+        identityKey,            
+      );
+
+      final sessionBuilder = SessionBuilder(_store, _store, _store, _store, address);
+      
+      await sessionBuilder.processPreKeyBundle(bundle);
+      debugPrint("E2EE Session established perfectly with $remoteUserId!");
+      return true;
+
+    } on DioException catch (e) {
+      if (e.response?.statusCode == 404) {
+        debugPrint("Receiver $remoteUserId has not registered E2EE keys yet.");
+      } else {
+        debugPrint("Network error fetching bundle for $remoteUserId: ${e.message}");
+      }
+      return false;
+    } catch (e) {
+      debugPrint("Failed to establish E2EE session with $remoteUserId: $e");
+      return false;
+    }
+  }
+  
+  Future<Map<String, dynamic>> encryptMessage(
+    String remoteUserId,
+    String plaintext,
+  ) async {
+    debugPrint("SignalService: Encrypting message for $remoteUserId...");
+    final address = _getAddress(remoteUserId);
+    final sessionCipher = SessionCipher(
+      _store,
+      _store,
+      _store,
+      _store,
+      address,
+    );
+
+    final plaintextBytes = Uint8List.fromList(utf8.encode(plaintext));
+    final ciphertextMessage = await sessionCipher.encrypt(plaintextBytes);
+
+    debugPrint("SignalService: Encryption successful (Type ${ciphertextMessage.getType()}).");
+    return {
+      'type': ciphertextMessage.getType(),
+      'ciphertext': base64Encode(ciphertextMessage.serialize()),
+    };
+  }
+
+  Future<String> decryptMessage(
+    String remoteUserId,
+    String base64Ciphertext,
+    int type,
+  ) async {
+    debugPrint("SignalService: Decrypting message from $remoteUserId...");
+    final address = _getAddress(remoteUserId);
+    final sessionCipher = SessionCipher(
+      _store,
+      _store,
+      _store,
+      _store,
+      address,
+    );
+    final bytes = base64Decode(base64Ciphertext);
+
+    Uint8List plaintextBytes;
+
+    if (type == CiphertextMessage.prekeyType) {
+      plaintextBytes = await sessionCipher.decrypt(PreKeySignalMessage(bytes));
+    } else {
+      final signalMsg = SignalMessage.fromSerialized(bytes);
+      plaintextBytes = await sessionCipher.decryptFromSignal(signalMsg);
+    }
+
+    debugPrint("SignalService: Decryption successful!");
+    return utf8.decode(plaintextBytes);
+  }
+
+  Future<String?> getSafetyNumber(
+    String localUserId,
+    String remoteUserId,
+  ) async {
+    final localKeyPair = await _store.getIdentityKeyPair();
+    final remoteAddress = _getAddress(remoteUserId);
+    final remoteIdentity = await _store.getIdentity(remoteAddress);
+
+    if (remoteIdentity == null) return null;
+
+    final generator = NumericFingerprintGenerator(5200);
+
+    final fingerprint = generator.createFor(
+      1,
+      Uint8List.fromList(utf8.encode(localUserId)),
+      localKeyPair.getPublicKey(),
+      Uint8List.fromList(utf8.encode(remoteUserId)),
+      remoteIdentity,
+    );
+
+    return fingerprint.displayableFingerprint.localFingerprintNumbers;
+  }
+
+  Future<void> forceResetSession(String remoteUserId) async {
+    final address = _getAddress(remoteUserId);
+    await _store.deleteSession(address);
+    await establishSessionIfNeeded(remoteUserId);
+  }
+
+  Future<void> clearAllSessions() async {
+    final db = await DatabaseHelper.instance.database;
+    await db.delete('signal_sessions');
+  }
+}
\ No newline at end of file
diff --git a/mobile/lib/services/sqlite_signal_store.dart b/mobile/lib/services/sqlite_signal_store.dart
new file mode 100644
index 0000000..4695aed
--- /dev/null
+++ b/mobile/lib/services/sqlite_signal_store.dart
@@ -0,0 +1,258 @@
+import 'dart:convert';
+import 'dart:typed_data';
+import 'package:libsignal_protocol_dart/libsignal_protocol_dart.dart';
+import 'package:sqflite_sqlcipher/sqflite.dart';
+import 'db_services.dart';
+
+class SQLiteSignalStore implements SignalProtocolStore {
+  String _toB64(Uint8List bytes) => base64Encode(bytes);
+
+  Uint8List _fromB64(String b64) => base64Decode(b64);
+
+  Future<void> storeLocalData(
+    IdentityKeyPair keyPair,
+    int registrationId,
+  ) async {
+    final db = await DatabaseHelper.instance.database;
+    await db.insert('signal_local_keys', {
+      'id': 1,
+      'registration_id': registrationId,
+      'identity_key_pair': _toB64(keyPair.serialize()),
+    }, conflictAlgorithm: ConflictAlgorithm.replace);
+  }
+
+  @override
+  Future<IdentityKeyPair> getIdentityKeyPair() async {
+    final db = await DatabaseHelper.instance.database;
+    final res = await db.query('signal_local_keys', where: 'id = 1');
+    if (res.isEmpty) throw Exception("Local Identity Key not generated yet.");
+    return IdentityKeyPair.fromSerialized(
+      _fromB64(res.first['identity_key_pair'] as String),
+    );
+  }
+
+  @override
+  Future<int> getLocalRegistrationId() async {
+    final db = await DatabaseHelper.instance.database;
+    final res = await db.query('signal_local_keys', where: 'id = 1');
+    if (res.isEmpty) throw Exception("Registration ID not generated yet.");
+    return res.first['registration_id'] as int;
+  }
+
+  @override
+  Future<bool> saveIdentity(
+    SignalProtocolAddress address,
+    IdentityKey? identityKey,
+  ) async {
+    if (identityKey == null) return false;
+    final db = await DatabaseHelper.instance.database;
+    final existing = await getIdentity(address);
+
+    if (existing != null && existing != identityKey) {
+      await db.update(
+        'signal_identities',
+        {'identity_key': _toB64(identityKey.serialize())},
+        where: 'address = ?',
+        whereArgs: [address.getName()],
+      );
+      return true;
+    }
+
+    await db.insert('signal_identities', {
+      'address': address.getName(),
+      'identity_key': _toB64(identityKey.serialize()),
+    }, conflictAlgorithm: ConflictAlgorithm.replace);
+
+    return false;
+  }
+
+  @override
+  Future<IdentityKey?> getIdentity(SignalProtocolAddress address) async {
+    final db = await DatabaseHelper.instance.database;
+    final res = await db.query(
+      'signal_identities',
+      where: 'address = ?',
+      whereArgs: [address.getName()],
+    );
+    if (res.isEmpty) return null;
+
+    return IdentityKey.fromBytes(
+      _fromB64(res.first['identity_key'] as String),
+      0,
+    );
+  }
+
+  @override
+  Future<bool> isTrustedIdentity(
+    SignalProtocolAddress address,
+    IdentityKey? identityKey,
+    Direction direction,
+  ) async {
+    if (identityKey == null) return false;
+    final trusted = await getIdentity(address);
+    return trusted == null || trusted == identityKey;
+  }
+
+  @override
+  Future<PreKeyRecord> loadPreKey(int preKeyId) async {
+    final db = await DatabaseHelper.instance.database;
+    final res = await db.query(
+      'signal_prekeys',
+      where: 'key_id = ?',
+      whereArgs: [preKeyId],
+    );
+    if (res.isEmpty) throw InvalidKeyIdException("No prekey found");
+    return PreKeyRecord.fromBuffer(_fromB64(res.first['record'] as String));
+  }
+
+  @override
+  Future<void> storePreKey(int preKeyId, PreKeyRecord record) async {
+    final db = await DatabaseHelper.instance.database;
+    await db.insert('signal_prekeys', {
+      'key_id': preKeyId,
+      'record': _toB64(record.serialize()),
+    }, conflictAlgorithm: ConflictAlgorithm.replace);
+  }
+
+  @override
+  Future<bool> containsPreKey(int preKeyId) async {
+    final db = await DatabaseHelper.instance.database;
+    final res = await db.query(
+      'signal_prekeys',
+      where: 'key_id = ?',
+      whereArgs: [preKeyId],
+    );
+    return res.isNotEmpty;
+  }
+
+  @override
+  Future<void> removePreKey(int preKeyId) async {
+    final db = await DatabaseHelper.instance.database;
+    await db.delete(
+      'signal_prekeys',
+      where: 'key_id = ?',
+      whereArgs: [preKeyId],
+    );
+  }
+
+  @override
+  Future<SignedPreKeyRecord> loadSignedPreKey(int signedPreKeyId) async {
+    final db = await DatabaseHelper.instance.database;
+    final res = await db.query(
+      'signal_signed_prekeys',
+      where: 'key_id = ?',
+      whereArgs: [signedPreKeyId],
+    );
+    if (res.isEmpty) throw InvalidKeyIdException("No signed prekey found");
+
+    return SignedPreKeyRecord.fromSerialized(
+      _fromB64(res.first['record'] as String),
+    );
+  }
+
+  @override
+  Future<List<SignedPreKeyRecord>> loadSignedPreKeys() async {
+    final db = await DatabaseHelper.instance.database;
+    final res = await db.query('signal_signed_prekeys');
+    return res
+        .map(
+          (row) => SignedPreKeyRecord.fromSerialized(
+            _fromB64(row['record'] as String),
+          ),
+        )
+        .toList();
+  }
+
+  @override
+  Future<void> storeSignedPreKey(
+    int signedPreKeyId,
+    SignedPreKeyRecord record,
+  ) async {
+    final db = await DatabaseHelper.instance.database;
+    await db.insert('signal_signed_prekeys', {
+      'key_id': signedPreKeyId,
+      'record': _toB64(record.serialize()),
+    }, conflictAlgorithm: ConflictAlgorithm.replace);
+  }
+
+  @override
+  Future<bool> containsSignedPreKey(int signedPreKeyId) async {
+    final db = await DatabaseHelper.instance.database;
+    final res = await db.query(
+      'signal_signed_prekeys',
+      where: 'key_id = ?',
+      whereArgs: [signedPreKeyId],
+    );
+    return res.isNotEmpty;
+  }
+
+  @override
+  Future<void> removeSignedPreKey(int signedPreKeyId) async {
+    final db = await DatabaseHelper.instance.database;
+    await db.delete(
+      'signal_signed_prekeys',
+      where: 'key_id = ?',
+      whereArgs: [signedPreKeyId],
+    );
+  }
+
+  @override
+  Future<SessionRecord> loadSession(SignalProtocolAddress address) async {
+    final db = await DatabaseHelper.instance.database;
+    final res = await db.query(
+      'signal_sessions',
+      where: 'address = ?',
+      whereArgs: [address.getName()],
+    );
+    if (res.isEmpty) {
+      return SessionRecord();
+    }
+    return SessionRecord.fromSerialized(
+      _fromB64(res.first['record'] as String),
+    );
+  }
+
+  @override
+  Future<List<int>> getSubDeviceSessions(String name) async {
+    return [1]; 
+  }
+
+  @override
+  Future<void> storeSession(
+    SignalProtocolAddress address,
+    SessionRecord record,
+  ) async {
+    final db = await DatabaseHelper.instance.database;
+    await db.insert('signal_sessions', {
+      'address': address.getName(),
+      'record': _toB64(record.serialize()),
+    }, conflictAlgorithm: ConflictAlgorithm.replace);
+  }
+
+  @override
+  Future<bool> containsSession(SignalProtocolAddress address) async {
+    final db = await DatabaseHelper.instance.database;
+    final res = await db.query(
+      'signal_sessions',
+      where: 'address = ?',
+      whereArgs: [address.getName()],
+    );
+    return res.isNotEmpty;
+  }
+
+  @override
+  Future<void> deleteSession(SignalProtocolAddress address) async {
+    final db = await DatabaseHelper.instance.database;
+    await db.delete(
+      'signal_sessions',
+      where: 'address = ?',
+      whereArgs: [address.getName()],
+    );
+  }
+
+  @override
+  Future<void> deleteAllSessions(String name) async {
+    final db = await DatabaseHelper.instance.database;
+    await db.delete('signal_sessions', where: 'address = ?', whereArgs: [name]);
+  }
+}
diff --git a/mobile/lib/services/ws_service.dart b/mobile/lib/services/ws_service.dart
index 2b5f3fa..306cb4d 100644
--- a/mobile/lib/services/ws_service.dart
+++ b/mobile/lib/services/ws_service.dart
@@ -75,7 +75,6 @@ class WebSocketService {
     required String groupId,
     required String content,
     String? replyToMessageId,
-    required String senderId,
   }) {
     emit({
       "type": "chat",
@@ -83,7 +82,6 @@ class WebSocketService {
       "group_id": groupId,
       "content": content,
       "reply_to_message_id": replyToMessageId,
-      "sender_id": senderId,
     });
   }
 
diff --git a/mobile/pubspec.lock b/mobile/pubspec.lock
index 13ece19..7db0146 100644
--- a/mobile/pubspec.lock
+++ b/mobile/pubspec.lock
@@ -1,6 +1,14 @@
 # Generated by pub
 # See https://dart.dev/tools/pub/glossary#lockfile
 packages:
+  adaptive_number:
+    dependency: transitive
+    description:
+      name: adaptive_number
+      sha256: "3a567544e9b5c9c803006f51140ad544aedc79604fd4f3f2c1380003f97c1d77"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.0"
   app_links:
     dependency: "direct main"
     description:
@@ -129,6 +137,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.0"
+  convert:
+    dependency: transitive
+    description:
+      name: convert
+      sha256: b30acd5944035672bc15c6b7a8b47d773e41e2f17de064350988c5d02adb1c68
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.1.2"
   crypto:
     dependency: transitive
     description:
@@ -157,10 +173,18 @@ packages:
     dependency: transitive
     description:
       name: dio_web_adapter
-      sha256: dd58dc3861eb36edb13b217efc006a1c21e5bbc341de8c229b85634fa5e362e4
+      sha256: "0786d0b7295a373de356fc0af4f6f1d0ab2844ed31b19dfc5e7556b70e24212c"
       url: "https://pub.dev"
     source: hosted
-    version: "2.2.0"
+    version: "2.2.1"
+  ed25519_edwards:
+    dependency: transitive
+    description:
+      name: ed25519_edwards
+      sha256: "6ce0112d131327ec6d42beede1e5dfd526069b18ad45dcf654f15074ad9276cd"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.3.1"
   fake_async:
     dependency: transitive
     description:
@@ -258,18 +282,18 @@ packages:
     dependency: transitive
     description:
       name: flutter_secure_storage_linux
-      sha256: a5f35ddab43cf5c8215d2feb4ce1957851f28c5c37e6f04335066a0602087bf5
+      sha256: "76fa9c841b3b1619fc5b5bc36efc7d158fa2356f223b6caeb1d0c80a54168546"
       url: "https://pub.dev"
     source: hosted
-    version: "3.0.1"
+    version: "3.0.2"
   flutter_secure_storage_platform_interface:
     dependency: transitive
     description:
       name: flutter_secure_storage_platform_interface
-      sha256: "8ceea1223bee3c6ac1a22dabd8feefc550e4729b3675de4b5900f55afcb435d6"
+      sha256: "788060052712555182aba55ecb5f8b6e5cb9cfe8f776c83249a61fe3ce877db4"
       url: "https://pub.dev"
     source: hosted
-    version: "2.0.1"
+    version: "2.0.3"
   flutter_secure_storage_web:
     dependency: transitive
     description:
@@ -316,10 +340,10 @@ packages:
     dependency: transitive
     description:
       name: hooks
-      sha256: "9a62a50b50b769a737bc0a8ff381f333529df3ab746b2f6b02e83760231455ba"
+      sha256: "03a564c3704524ee0f7fc56fc621e8796cc2eb8c24d1f1a33b34979815b285c4"
       url: "https://pub.dev"
     source: hosted
-    version: "2.0.2"
+    version: "2.1.0"
   http_parser:
     dependency: transitive
     description:
@@ -348,18 +372,26 @@ packages:
     dependency: transitive
     description:
       name: jni
-      sha256: c2230682d5bc2362c1c9e8d3c7f406d9cbba23ab3f2e203a025dd47e0fb2e68f
+      sha256: f038e58b4dc2c9037f50e233175086337e0b305e356d28211bf55f21c504cbd3
       url: "https://pub.dev"
     source: hosted
-    version: "1.0.0"
+    version: "1.0.3"
   jni_flutter:
     dependency: transitive
     description:
       name: jni_flutter
-      sha256: "8b59e590786050b1cd866677dddaf76b1ade5e7bc751abe04b86e84d379d3ba6"
+      sha256: "7b717011ea40d04fd47c2731d3d1d36eb99eba3435c2753d62489e8c3c9991d5"
       url: "https://pub.dev"
     source: hosted
-    version: "1.0.1"
+    version: "1.0.2"
+  jni_util:
+    dependency: transitive
+    description:
+      name: jni_util
+      sha256: "1ba86da04a5f2bf18fde2edb235587e70c5b0fc5bd4ba955f46b00942c3fc35f"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.0"
   json_annotation:
     dependency: transitive
     description:
@@ -400,6 +432,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.0.2"
+  libsignal_protocol_dart:
+    dependency: "direct main"
+    description:
+      name: libsignal_protocol_dart
+      sha256: "3ed4455f09c7299934a6b9ca0028daff87940d446142056e1ec25997de0e41bf"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.8.2"
   lints:
     dependency: transitive
     description:
@@ -428,10 +468,10 @@ packages:
     dependency: transitive
     description:
       name: matcher
-      sha256: dc0b7dc7651697ea4ff3e69ef44b0407ea32c487a39fff6a4004fa585e901861
+      sha256: "31bd099b47c10cd1aeb55146a2d46ce0277630ecef3f7dae54ad7873f36696cd"
       url: "https://pub.dev"
     source: hosted
-    version: "0.12.19"
+    version: "0.12.20"
   material_color_utilities:
     dependency: transitive
     description:
@@ -444,10 +484,10 @@ packages:
     dependency: transitive
     description:
       name: meta
-      sha256: "1741988757a65eb6b36abe716829688cf01910bbf91c34354ff7ec1c3de2b349"
+      sha256: "307249ce4ff29d58a18e97f6345f539382eb9c9c29ecda628900f31de0443dd9"
       url: "https://pub.dev"
     source: hosted
-    version: "1.18.0"
+    version: "1.19.0"
   mime:
     dependency: transitive
     description:
@@ -476,18 +516,26 @@ packages:
     dependency: transitive
     description:
       name: objective_c
-      sha256: "6cb691c686fa2838c6deb34980d426145c2a5d537491cb83d463c33cdbc726ed"
+      sha256: b7fb95a6d9a4f009edd63dc5ac69f07420b23a16161c6dd8660290b59c602e8e
+      url: "https://pub.dev"
+    source: hosted
+    version: "9.5.0"
+  optional:
+    dependency: transitive
+    description:
+      name: optional
+      sha256: f80327d7a3335a0be68418072668043c7ab291df575c21aa42e0c5633641da39
       url: "https://pub.dev"
     source: hosted
-    version: "9.4.1"
+    version: "6.1.0+1"
   package_config:
     dependency: transitive
     description:
       name: package_config
-      sha256: f096c55ebb7deb7e384101542bfba8c52696c1b56fca2eb62827989ef2353bbc
+      sha256: ffcf4cf3d6c0b74ac43708d9f56625506e8a68aa935abe9d267a7330f320eb5d
       url: "https://pub.dev"
     source: hosted
-    version: "2.2.0"
+    version: "3.0.0"
   path:
     dependency: "direct main"
     description:
@@ -568,14 +616,30 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.8"
+  pointycastle:
+    dependency: transitive
+    description:
+      name: pointycastle
+      sha256: "92aa3841d083cc4b0f4709b5c74fd6409a3e6ba833ffc7dc6a8fee096366acf5"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.0.0"
   posix:
     dependency: transitive
     description:
       name: posix
-      sha256: "185ef7606574f789b40f289c233efa52e96dead518aed988e040a10737febb07"
+      sha256: bc1bad54ad2b735816e31f8d4600cfde6c7839975085ddfbca48b6c9f7c4044e
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.5.2"
+  protobuf:
+    dependency: transitive
+    description:
+      name: protobuf
+      sha256: "75ec242d22e950bdcc79ee38dd520ce4ee0bc491d7fadc4ea47694604d22bf06"
       url: "https://pub.dev"
     source: hosted
-    version: "6.5.0"
+    version: "6.0.0"
   provider:
     dependency: "direct main"
     description:
@@ -612,10 +676,10 @@ packages:
     dependency: transitive
     description:
       name: record_use
-      sha256: "2551bd8eecfe95d14ae75f6021ad0248be5c27f138c2ec12fcb52b500b3ba1ed"
+      sha256: "3b4ab682aff40175afca6ff090cc5aa7ce9dafe8dfbae1537a6c678e6678baee"
       url: "https://pub.dev"
     source: hosted
-    version: "0.6.0"
+    version: "1.1.0"
   scrollable_positioned_list:
     dependency: "direct main"
     description:
@@ -705,10 +769,10 @@ packages:
     dependency: "direct main"
     description:
       name: sqflite_sqlcipher
-      sha256: ba7733c5514cf0ccb0331997b771a890f73678bcd84cdfb5f7487a88a71f1738
+      sha256: "50d05fe0495ed96a85503d9850a49c0936502f44fdba96f403c97e4c9c7043e7"
       url: "https://pub.dev"
     source: hosted
-    version: "3.4.0"
+    version: "3.4.1"
   stack_trace:
     dependency: transitive
     description:
@@ -737,10 +801,10 @@ packages:
     dependency: transitive
     description:
       name: synchronized
-      sha256: "93b153dcb6a26dcddee6ca087dd634b53e38c10b5aa163e8e49501a776456153"
+      sha256: "61894a1956de6b4fc1aefd0892e109514a1a706cbece3ac59decd90ff5a7a423"
       url: "https://pub.dev"
     source: hosted
-    version: "3.4.1"
+    version: "3.4.1+1"
   term_glyph:
     dependency: transitive
     description:
@@ -753,10 +817,10 @@ packages:
     dependency: transitive
     description:
       name: test_api
-      sha256: "949a932224383300f01be9221c39180316445ecb8e7547f70a41a35bf421fb9e"
+      sha256: "2a122cbe059f8b610d3a5415f42e255b6c17b1f21eee1d960f31080237fb4f11"
       url: "https://pub.dev"
     source: hosted
-    version: "0.7.11"
+    version: "0.7.12"
   typed_data:
     dependency: transitive
     description:
@@ -841,10 +905,10 @@ packages:
     dependency: transitive
     description:
       name: vector_math
-      sha256: d530bd74fea330e6e364cda7a85019c434070188383e1cd8d9777ee586914c5b
+      sha256: f36f9f3be64c6198714492bb455c11056e33e2f85d9a0b676a48301e44fdcf47
       url: "https://pub.dev"
     source: hosted
-    version: "2.2.0"
+    version: "2.4.2"
   vm_service:
     dependency: transitive
     description:
@@ -881,10 +945,18 @@ packages:
     dependency: transitive
     description:
       name: win32
-      sha256: ba6f4bba816c8d7e3c1580e170f3786d216951cc6b94babc3b814c08d2cb2738
+      sha256: a0b93865d5644f11cf6a8c3f6db909f1ec168958b5805f6cc684adea957cd63d
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.4.0"
+  x25519:
+    dependency: transitive
+    description:
+      name: x25519
+      sha256: cec3c125f0d934dccba6c4cab48f3fbf866dc78895dcc5a1584d35b0a845005b
       url: "https://pub.dev"
     source: hosted
-    version: "6.3.0"
+    version: "0.1.1"
   xdg_directories:
     dependency: transitive
     description:
diff --git a/mobile/pubspec.yaml b/mobile/pubspec.yaml
index 8c12d16..d7524da 100644
--- a/mobile/pubspec.yaml
+++ b/mobile/pubspec.yaml
@@ -49,6 +49,7 @@ dependencies:
   shared_preferences: ^2.5.5
   scrollable_positioned_list: ^0.3.8
   path: ^1.9.1
+  libsignal_protocol_dart: ^0.8.2
   
 launcher_name:
   default: "Elephant"