diff --git a/Lagrange.Core/Internal/Packets/Action/HttpConn/ServerAddr.cs b/Lagrange.Core/Internal/Packets/Action/HttpConn/ServerAddr.cs
index 7b9ba70..ef14ddd 100644
--- a/Lagrange.Core/Internal/Packets/Action/HttpConn/ServerAddr.cs
+++ b/Lagrange.Core/Internal/Packets/Action/HttpConn/ServerAddr.cs
@@ -3,7 +3,7 @@ using ProtoBuf;
 namespace Lagrange.Core.Internal.Packets.Action.HttpConn;
 
 [ProtoContract]
-public class ServerAddr
+internal class ServerAddr
 {
     [ProtoMember(1)] public uint Type { get; set; }
     
diff --git a/Lagrange.Core/Internal/Packets/Action/HttpConn/ServerInfo.cs b/Lagrange.Core/Internal/Packets/Action/HttpConn/ServerInfo.cs
index 30ac18f..83f2786 100644
--- a/Lagrange.Core/Internal/Packets/Action/HttpConn/ServerInfo.cs
+++ b/Lagrange.Core/Internal/Packets/Action/HttpConn/ServerInfo.cs
@@ -5,7 +5,7 @@ namespace Lagrange.Core.Internal.Packets.Action.HttpConn;
 #pragma warning disable CS8618
 
 [ProtoContract]
-public class ServerInfo
+internal class ServerInfo
 {
     [ProtoMember(1)] public uint ServiceType { get; set; }
     
diff --git a/Lagrange.Core/Internal/Packets/Login/NTLogin/NTLoginHttpRequest.cs b/Lagrange.Core/Internal/Packets/Login/NTLogin/NTLoginHttpRequest.cs
index 62a5af0..545fc2c 100644
--- a/Lagrange.Core/Internal/Packets/Login/NTLogin/NTLoginHttpRequest.cs
+++ b/Lagrange.Core/Internal/Packets/Login/NTLogin/NTLoginHttpRequest.cs
@@ -5,7 +5,7 @@ using System.Text.Json.Serialization;
 
 namespace Lagrange.Core.Internal.Packets.Login.NTLogin;
 
-public class NTLoginHttpRequest
+internal class NTLoginHttpRequest
 {
     [JsonPropertyName("appid")] public long Appid { get; set; }
 
diff --git a/Lagrange.Core/Internal/Packets/Login/NTLogin/NTLoginHttpResponse.cs b/Lagrange.Core/Internal/Packets/Login/NTLogin/NTLoginHttpResponse.cs
index b2a03a6..1249f18 100644
--- a/Lagrange.Core/Internal/Packets/Login/NTLogin/NTLoginHttpResponse.cs
+++ b/Lagrange.Core/Internal/Packets/Login/NTLogin/NTLoginHttpResponse.cs
@@ -5,7 +5,7 @@ using System.Text.Json.Serialization;
 
 namespace Lagrange.Core.Internal.Packets.Login.NTLogin;
 
-public class NTLoginHttpResponse
+internal class NTLoginHttpResponse
 {
     [JsonPropertyName("retCode")] public int RetCode { get; set; }
 
diff --git a/Lagrange.Core/Internal/Packets/Service/Oidb/Request/OidbSvcTrpcTcp0x7C1_1.cs b/Lagrange.Core/Internal/Packets/Service/Oidb/Request/OidbSvcTrpcTcp0x7C1_1.cs
index 8b00cfe..7b2d664 100644
--- a/Lagrange.Core/Internal/Packets/Service/Oidb/Request/OidbSvcTrpcTcp0x7C1_1.cs
+++ b/Lagrange.Core/Internal/Packets/Service/Oidb/Request/OidbSvcTrpcTcp0x7C1_1.cs
@@ -6,7 +6,7 @@ namespace Lagrange.Core.Internal.Packets.Service.Oidb.Request;
 
 [ProtoContract]
 [OidbSvcTrpcTcp(0x7c1, 1)]
-public class OidbSvcTrpcTcp0x7C1_1
+internal class OidbSvcTrpcTcp0x7C1_1
 {
     [ProtoMember(1)] public uint Field1 { get; set; } // 1
     
diff --git a/Lagrange.Core/Internal/Packets/Service/Oidb/Request/OidbSvcTrpcTcp0xE37_1200.cs b/Lagrange.Core/Internal/Packets/Service/Oidb/Request/OidbSvcTrpcTcp0xE37_1200.cs
index b5d2111..de9f2c9 100644
--- a/Lagrange.Core/Internal/Packets/Service/Oidb/Request/OidbSvcTrpcTcp0xE37_1200.cs
+++ b/Lagrange.Core/Internal/Packets/Service/Oidb/Request/OidbSvcTrpcTcp0xE37_1200.cs
@@ -24,7 +24,7 @@ internal class OidbSvcTrpcTcp0xE37_1200
 }
 
 [ProtoContract]
-public class OidbSvcTrpcTcp0xE37_1200Body
+internal class OidbSvcTrpcTcp0xE37_1200Body
 {
     [ProtoMember(10)] public string ReceiverUid { get; set; }
     
diff --git a/Lagrange.Core/Internal/Packets/Service/Oidb/Request/OidbSvcTrpcTcp0xE37_800.cs b/Lagrange.Core/Internal/Packets/Service/Oidb/Request/OidbSvcTrpcTcp0xE37_800.cs
index 14a623f..849fbe5 100644
--- a/Lagrange.Core/Internal/Packets/Service/Oidb/Request/OidbSvcTrpcTcp0xE37_800.cs
+++ b/Lagrange.Core/Internal/Packets/Service/Oidb/Request/OidbSvcTrpcTcp0xE37_800.cs
@@ -9,7 +9,7 @@ namespace Lagrange.Core.Internal.Packets.Service.Oidb.Request;
 /// </summary>
 [ProtoContract]
 [OidbSvcTrpcTcp(0xE37, 800)]
-public class OidbSvcTrpcTcp0xE37_800
+internal class OidbSvcTrpcTcp0xE37_800
 {
     [ProtoMember(1)] public uint SubCommand => 800;
     
@@ -25,7 +25,7 @@ public class OidbSvcTrpcTcp0xE37_800
 }
 
 [ProtoContract]
-public class OidbSvcTrpcTcp0xE37_800Body
+internal class OidbSvcTrpcTcp0xE37_800Body
 {
     [ProtoMember(10)] public string SenderUid { get; set; }
     
diff --git a/Lagrange.Core/Internal/Packets/Service/Oidb/Response/OidbSvcTrpcTcp0x8FC_3Response.cs b/Lagrange.Core/Internal/Packets/Service/Oidb/Response/OidbSvcTrpcTcp0x8FC_3Response.cs
index 948456e..cdf425b 100644
--- a/Lagrange.Core/Internal/Packets/Service/Oidb/Response/OidbSvcTrpcTcp0x8FC_3Response.cs
+++ b/Lagrange.Core/Internal/Packets/Service/Oidb/Response/OidbSvcTrpcTcp0x8FC_3Response.cs
@@ -5,7 +5,7 @@ namespace Lagrange.Core.Internal.Packets.Service.Oidb.Response;
 // ReSharper disable InconsistentNaming
 
 [ProtoContract]
-public class OidbSvcTrpcTcp0x8FC_3Response
+internal class OidbSvcTrpcTcp0x8FC_3Response
 {
     [ProtoMember(1)] public uint GroupUin { get; set; }
 }
\ No newline at end of file
diff --git a/Lagrange.Core/Message/MessageElementAttribute.cs b/Lagrange.Core/Message/MessageElementAttribute.cs
index 4b0e768..9845dbb 100644
--- a/Lagrange.Core/Message/MessageElementAttribute.cs
+++ b/Lagrange.Core/Message/MessageElementAttribute.cs
@@ -1,7 +1,7 @@
 namespace Lagrange.Core.Message;
 
 [AttributeUsage(AttributeTargets.Class, AllowMultiple = true)]
-public class MessageElementAttribute : Attribute
+internal class MessageElementAttribute : Attribute
 {
     public Type Element { get; }
     
diff --git a/Lagrange.Core/Utility/Binary/Compression/GZip.cs b/Lagrange.Core/Utility/Binary/Compression/GZip.cs
index b4367d4..6254fc5 100644
--- a/Lagrange.Core/Utility/Binary/Compression/GZip.cs
+++ b/Lagrange.Core/Utility/Binary/Compression/GZip.cs
@@ -2,7 +2,7 @@ using System.IO.Compression;
 
 namespace Lagrange.Core.Utility.Binary.Compression;
 
-public static class GZip
+internal static class GZip
 {
     public static byte[] Inflate(byte[] input)
     {
diff --git a/Lagrange.Core/Utility/ImageResolver.cs b/Lagrange.Core/Utility/ImageResolver.cs
index da6e22f..6796aea 100644
--- a/Lagrange.Core/Utility/ImageResolver.cs
+++ b/Lagrange.Core/Utility/ImageResolver.cs
@@ -3,7 +3,7 @@ using BitConverter = Lagrange.Core.Utility.Binary.BitConverter;
 
 namespace Lagrange.Core.Utility;
 
-public static class ImageResolver
+internal static class ImageResolver
 {
     public static ImageFormat Resolve(byte[] image, out Vector2 size)
     {
@@ -66,7 +66,7 @@ public static class ImageResolver
     }
 }
 
-public enum ImageFormat
+internal enum ImageFormat
 {
     Unknown,
     Png,