diff --git a/Assets/Scripts/Entities/SyncBases/Inventory.cs b/Assets/Scripts/Entities/SyncBases/Inventory.cs
index fa162dd..28af025 100644
--- a/Assets/Scripts/Entities/SyncBases/Inventory.cs
+++ b/Assets/Scripts/Entities/SyncBases/Inventory.cs
@@ -1,6 +1,8 @@
 
+using Cyber.Console;
 using Cyber.Items;
 using Cyber.Networking;
+using Cyber.Networking.Serverside;
 using UnityEngine;
 using UnityEngine.Networking;
 
@@ -21,8 +23,23 @@ namespace Cyber.Entities.SyncBases {
         /// </summary>
         public Inventory() {
             Drive = new Drive(10f);
-            Drive.AddItem(ItemDB.Singleton.Get(0));
-            Drive.AddItem(ItemDB.Singleton.Get(1));
+            if (Server.IsRunning()) {
+                Drive.AddItem(ItemDB.Singleton.Get(0));
+                Drive.AddItem(ItemDB.Singleton.Get(1));
+            }
+        }
+
+        /// <summary>
+        /// Generates a checksum for the inventory
+        /// </summary>
+        /// <returns>A checksum of the IDs of the items</returns>
+        public override int GenerateChecksum() {
+            var Items = Drive.GetItems().ToArray();
+            int Checksum = 0;
+            for (int i = 0; i < Items.Length; i++) {
+                Checksum ^= Items[i].ID;
+            }
+            return Checksum;
         }
 
         /// <summary>
@@ -38,6 +55,8 @@ namespace Cyber.Entities.SyncBases {
         /// </summary>
         /// <param name="reader"></param>
         public override void Deserialize(NetworkReader reader) {
+            Debug.Log("Deserializing inventory!");
+
             byte[][] ByteArray = new byte[4][];
             ByteArray[0] = reader.ReadBytesAndSize();
             ByteArray[1] = reader.ReadBytesAndSize();
diff --git a/Assets/Scripts/Networking/Clientside/SyncHandler.cs b/Assets/Scripts/Networking/Clientside/SyncHandler.cs
index 7d172aa..c5775e9 100644
--- a/Assets/Scripts/Networking/Clientside/SyncHandler.cs
+++ b/Assets/Scripts/Networking/Clientside/SyncHandler.cs
@@ -1,6 +1,9 @@
 
+using Cyber.Console;
 using Cyber.Entities;
+using Cyber.Entities.SyncBases;
 using Cyber.Networking.Messages;
+using System.Collections.Generic;
 using UnityEngine.Networking;
 
 namespace Cyber.Networking.Clientside {
@@ -32,6 +35,20 @@ namespace Cyber.Networking.Clientside {
             if (LatestSyncID < SyncPacket.SyncPacketID) {
                 LatestSyncID = SyncPacket.SyncPacketID;
                 SyncPacket.ApplySync(message.reader);
+
+                int[] SyncBases = SyncPacket.ChecksummedSyncBases;
+                int[] Checksums = SyncPacket.Checksums;
+                if (SyncBases.Length > 0) {
+                    List<int> FailedSyncBases = new List<int>();
+                    for (int i = 0; i < SyncBases.Length; i++) {
+                        SyncBase SyncBase = SyncDB.Get(SyncBases[i]);
+                        if (SyncBase.GenerateChecksum() != Checksums[i]) {
+                            FailedSyncBases.Add(SyncBase.ID);
+                        }
+                    }
+
+                    Client.Send(PktType.FailedChecksums, new IntListPkt(FailedSyncBases.ToArray()));
+                }
             }
             // Otherwise disregard the sync.
 
diff --git a/Assets/Scripts/Networking/Messages/SyncPkt.cs b/Assets/Scripts/Networking/Messages/SyncPkt.cs
index 2eb9150..55c05a3 100644
--- a/Assets/Scripts/Networking/Messages/SyncPkt.cs
+++ b/Assets/Scripts/Networking/Messages/SyncPkt.cs
@@ -20,6 +20,16 @@ namespace Cyber.Networking.Messages {
         /// </summary>
         public int[] SyncedSyncBases;
 
+        /// <summary>
+        /// The Array of SyncIDs that have their hashes in this syncpacket
+        /// </summary>
+        public int[] ChecksummedSyncBases;
+
+        /// <summary>
+        /// The Array of Checksums that are sent with <see cref="ChecksummedSyncBases"/>.
+        /// </summary>
+        public int[] Checksums;
+
         private SyncDB SyncDB;
 
         /// <summary>
@@ -27,11 +37,15 @@ namespace Cyber.Networking.Messages {
         /// </summary>
         /// <param name="syncDB">SyncDB to sync from.</param>
         /// <param name="syncBases">The ID's of the SyncBases to sync.</param>
+        /// <param name="checksummedSyncBases"></param>
+        /// <param name="checksums"></param>
         /// <param name="syncPacketID">ID of the sync packet itself.</param>
-        public SyncPkt(SyncDB syncDB, int[] syncBases, int syncPacketID) {
+        public SyncPkt(SyncDB syncDB, int[] syncBases, int[] checksummedSyncBases, int[] checksums, int syncPacketID) {
             SyncPacketID = syncPacketID;
             SyncDB = syncDB;
             SyncedSyncBases = syncBases;
+            ChecksummedSyncBases = checksummedSyncBases;
+            Checksums = checksums;
         }
 
         /// <summary>
@@ -40,6 +54,8 @@ namespace Cyber.Networking.Messages {
         /// <param name="syncDB">SyncBase to sync to.</param>
         public SyncPkt(SyncDB syncDB) {
             SyncDB = syncDB;
+            ChecksummedSyncBases = new int[0];
+            Checksums = new int[0];
         }
 
         /// <summary>
@@ -65,6 +81,25 @@ namespace Cyber.Networking.Messages {
             foreach (int syncId in SyncedSyncBases) {
                 SyncDB.Get(syncId).Deserialize(reader);
             }
+
+            bool checksums = reader.ReadBoolean();
+
+            if (checksums) {
+                byte[][] SummedIdsByteArray = new byte[4][];
+                SummedIdsByteArray[0] = reader.ReadBytesAndSize();
+                SummedIdsByteArray[1] = reader.ReadBytesAndSize();
+                SummedIdsByteArray[2] = reader.ReadBytesAndSize();
+                SummedIdsByteArray[3] = reader.ReadBytesAndSize();
+
+                byte[][] SumsByteArray = new byte[4][];
+                SumsByteArray[0] = reader.ReadBytesAndSize();
+                SumsByteArray[1] = reader.ReadBytesAndSize();
+                SumsByteArray[2] = reader.ReadBytesAndSize();
+                SumsByteArray[3] = reader.ReadBytesAndSize();
+
+                ChecksummedSyncBases = NetworkHelper.DeserializeIntArray(SummedIdsByteArray);
+                Checksums = NetworkHelper.DeserializeIntArray(SumsByteArray);
+            }
         }
 
         /// <summary>
@@ -74,15 +109,33 @@ namespace Cyber.Networking.Messages {
         public override void Serialize(NetworkWriter writer) {
             writer.Write(SyncPacketID);
 
-            byte[][] ByteArray = NetworkHelper.SerializeIntArray(SyncedSyncBases);
-            writer.WriteBytesFull(ByteArray[0]);
-            writer.WriteBytesFull(ByteArray[1]);
-            writer.WriteBytesFull(ByteArray[2]);
-            writer.WriteBytesFull(ByteArray[3]);
+            byte[][] SyncedIdsByteArray = NetworkHelper.SerializeIntArray(SyncedSyncBases);
+            writer.WriteBytesFull(SyncedIdsByteArray[0]);
+            writer.WriteBytesFull(SyncedIdsByteArray[1]);
+            writer.WriteBytesFull(SyncedIdsByteArray[2]);
+            writer.WriteBytesFull(SyncedIdsByteArray[3]);
             
             foreach (int syncId in SyncedSyncBases) {
                 SyncDB.Get(syncId).Serialize(writer);
             }
+
+            if (ChecksummedSyncBases.Length == 0) {
+                writer.Write(false);
+            } else {
+                writer.Write(true);
+
+                byte[][] SummedIdsByteArray = NetworkHelper.SerializeIntArray(ChecksummedSyncBases);
+                writer.WriteBytesFull(SummedIdsByteArray[0]);
+                writer.WriteBytesFull(SummedIdsByteArray[1]);
+                writer.WriteBytesFull(SummedIdsByteArray[2]);
+                writer.WriteBytesFull(SummedIdsByteArray[3]);
+                
+                byte[][] SumsByteArray = NetworkHelper.SerializeIntArray(Checksums);
+                writer.WriteBytesFull(SumsByteArray[0]);
+                writer.WriteBytesFull(SumsByteArray[1]);
+                writer.WriteBytesFull(SumsByteArray[2]);
+                writer.WriteBytesFull(SumsByteArray[3]);
+            }
         }
 
     }
diff --git a/Assets/Scripts/Networking/PktType.cs b/Assets/Scripts/Networking/PktType.cs
index c84c02c..644ba6b 100644
--- a/Assets/Scripts/Networking/PktType.cs
+++ b/Assets/Scripts/Networking/PktType.cs
@@ -60,5 +60,10 @@ namespace Cyber.Networking {
         /// </summary>
         public const short Disconnect = 209;
 
+        /// <summary>
+        /// Packet containing SyncBase id's of the SyncBases which failed the checksum test.
+        /// </summary>
+        public const short FailedChecksums = 210;
+
     }
 }
\ No newline at end of file
diff --git a/Assets/Scripts/Networking/Serverside/Server.cs b/Assets/Scripts/Networking/Serverside/Server.cs
index 5b97de5..b02269f 100644
--- a/Assets/Scripts/Networking/Serverside/Server.cs
+++ b/Assets/Scripts/Networking/Serverside/Server.cs
@@ -148,6 +148,7 @@ namespace Cyber.Networking.Serverside {
             NetworkServer.RegisterHandler(PktType.Interact, HandlePacket);
             NetworkServer.RegisterHandler(PktType.ClientSync, HandlePacket);
             NetworkServer.RegisterHandler(PktType.Disconnect, HandlePacket);
+            NetworkServer.RegisterHandler(PktType.FailedChecksums, HandlePacket);
 
             NetworkServer.RegisterHandler(MsgType.Connect, OnConnected);
             NetworkServer.RegisterHandler(MsgType.Disconnect, OnDisconnected);
@@ -232,6 +233,13 @@ namespace Cyber.Networking.Serverside {
             case PktType.Disconnect:
                 msg.conn.Disconnect();
                 break;
+            case PktType.FailedChecksums:
+                IntListPkt FailedSyncs = new IntListPkt();
+                FailedSyncs.Deserialize(msg.reader);
+                foreach (int SyncBaseId in FailedSyncs.IdList) {
+                    Syncer.DirtSyncBase(SyncBaseId);
+                }
+                break;
             default:
                 Debug.LogError("Received an unknown packet, id: " + msg.msgType);
                 Term.Println("Received an unknown packet, id: " + msg.msgType);
diff --git a/Assets/Scripts/Networking/Serverside/Syncer.cs b/Assets/Scripts/Networking/Serverside/Syncer.cs
index 13af6fd..bcbe82c 100644
--- a/Assets/Scripts/Networking/Serverside/Syncer.cs
+++ b/Assets/Scripts/Networking/Serverside/Syncer.cs
@@ -31,6 +31,9 @@ namespace Cyber.Networking.Serverside {
         /// </summary>
         /// <param name="syncBaseID">The ID of the SyncBase. See <see cref="SyncBase.ID"/></param>
         public void DirtSyncBase(int syncBaseID) {
+            if (DirtySyncBases.Contains(syncBaseID)) {
+                return;
+            }
             DirtySyncBases.Add(syncBaseID);
         }
 
@@ -51,6 +54,8 @@ namespace Cyber.Networking.Serverside {
             if (TimeSinceLastTick >= TickInterval) {
 
                 var Categorized = Database.GetCategorizedDatabase();
+                List<int> checksummedIds = new List<int>();
+                List<int> checksums = new List<int>();
 
                 foreach (Type type in Categorized.Keys) {
                     SyncHandletype Handletype = Database.GetSyncHandletypes()[type];
@@ -59,6 +64,13 @@ namespace Cyber.Networking.Serverside {
                             bool Contains = DirtySyncBases.Contains(SyncBaseID);
                             if (Contains == Handletype.RequireHash || Contains) {
                                 QueueSyncBase(SyncBaseID);
+                                if (Contains) {
+                                    DirtySyncBases.Remove(SyncBaseID);
+                                }
+                            }
+                            if (Handletype.RequireHash) {
+                                checksummedIds.Add(SyncBaseID);
+                                checksums.Add(Database.Get(SyncBaseID).GenerateChecksum());
                             }
                         }
                     }
@@ -66,11 +78,10 @@ namespace Cyber.Networking.Serverside {
 
                 if (QueuedSyncs.Count > 0) {
                     int[] SyncIDs = QueuedSyncs.ToArray();
-                    SyncPkt SyncPacket = new SyncPkt(Database, SyncIDs, SyncPacketID++);
+                    SyncPkt SyncPacket = new SyncPkt(Database, SyncIDs, checksummedIds.ToArray(), checksums.ToArray(), SyncPacketID++);
                     Server.SendToAllByChannel(PktType.Sync, SyncPacket, NetworkChannelID.Unreliable);
-
+                    
                     QueuedSyncs.Clear();
-                    DirtySyncBases.Clear();
                 }