diff --git a/AyCode.Entities/AyCode.Entities.csproj b/AyCode.Entities/AyCode.Entities.csproj
index 3ad0559..c3047fd 100644
--- a/AyCode.Entities/AyCode.Entities.csproj
+++ b/AyCode.Entities/AyCode.Entities.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>net8.0</TargetFramework>
diff --git a/AyCode.Entities/Groups/GroupBase.cs b/AyCode.Entities/Groups/GroupBase.cs
new file mode 100644
index 0000000..91365d5
--- /dev/null
+++ b/AyCode.Entities/Groups/GroupBase.cs
@@ -0,0 +1,31 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using AyCode.Interfaces.Groups;
+
+namespace AyCode.Entities.Groups
+{
+    //[Table("Groups")]
+    public class GroupBase : IGroupBase
+    {
+        public GroupBase() { }
+
+        public GroupBase(bool isPublic) : this(Guid.NewGuid(), isPublic) { }
+        public GroupBase(Guid id, bool isPublic) : this()
+        {
+            Id = id;
+            IsPublic = isPublic;            
+        }      
+
+        //[Key, DatabaseGenerated(DatabaseGeneratedOption.None)]
+        public Guid Id { get; set; }
+        public bool IsPublic { get; set; }        
+        public DateTime Created { get; set; }
+        public DateTime Modified { get; set; }
+    }
+}
+
diff --git a/AyCode.Entities/Messages/MessageBase.cs b/AyCode.Entities/Messages/NoticeBase.cs
similarity index 69%
rename from AyCode.Entities/Messages/MessageBase.cs
rename to AyCode.Entities/Messages/NoticeBase.cs
index 2feb408..fd0c56c 100644
--- a/AyCode.Entities/Messages/MessageBase.cs
+++ b/AyCode.Entities/Messages/NoticeBase.cs
@@ -6,14 +6,14 @@ using AyCode.Interfaces.Messages;
 
 namespace AyCode.Entities.Messages
 {
-    [Table("Messages")]
-    public class MessageBase : IMessageBase
+    [Table("Notices")]
+    public class NoticeBase : INoticeBase
     {
         
-        public MessageBase() { }
+        public NoticeBase() { }
 
-        public MessageBase(Guid senderId, Guid receiverId, string message) : this(Guid.NewGuid(), senderId, receiverId, message) { }
-        public MessageBase(Guid id, Guid senderId, Guid receiverId, string message) : this()
+        public NoticeBase(Guid senderId, Guid receiverId, string message) : this(Guid.NewGuid(), senderId, receiverId, message) { }
+        public NoticeBase(Guid id, Guid senderId, Guid receiverId, string message) : this()
         {
             Id = id;
             SenderId = senderId;
@@ -23,14 +23,15 @@ namespace AyCode.Entities.Messages
        
 
         [Key, DatabaseGenerated(DatabaseGeneratedOption.None)]
+        public Guid Id { get; set; }
         public Guid SenderId { get; set; }
 
         public Guid ReceiverId { get; set; }
 
         public string Message { get; set; }
 
-        public Guid Id { get; set; }
         public DateTime Created { get; set; }
         public DateTime Modified { get; set; }
+
     }
 }
diff --git a/AyCode.Entities/ServiceProviders/ServiceProviderBase.cs b/AyCode.Entities/ServiceProviders/ServiceProviderBase.cs
new file mode 100644
index 0000000..4a0f7da
--- /dev/null
+++ b/AyCode.Entities/ServiceProviders/ServiceProviderBase.cs
@@ -0,0 +1,32 @@
+
+using System.ComponentModel.DataAnnotations.Schema;
+using System.ComponentModel.DataAnnotations;
+using AyCode.Interfaces.ServiceProviders;
+
+namespace AyCode.Entities.ServiceProviders
+{
+    [Table("ServiceProviders")]
+    public class ServiceProviderBase : IServiceProviderBase
+    {
+        public ServiceProviderBase() { }
+
+        public ServiceProviderBase(string name, Guid ownerId ) : this(Guid.NewGuid(), name, ownerId) { }
+        public ServiceProviderBase(Guid id, string name, Guid ownerId) : this()
+        {
+            Id = id;
+            Name = name;
+            OwnerId = ownerId;
+        }
+
+        
+
+        [Key, DatabaseGenerated(DatabaseGeneratedOption.None)]
+        public Guid Id { get; set; }
+        public string Name { get; set; }
+        public Guid OwnerId { get; set; }        
+
+        public DateTime Created { get; set; }
+        public DateTime Modified { get; set; }
+        
+    }
+}
diff --git a/AyCode.Interfaces/Groups/IGroupBase.cs b/AyCode.Interfaces/Groups/IGroupBase.cs
new file mode 100644
index 0000000..0aaa942
--- /dev/null
+++ b/AyCode.Interfaces/Groups/IGroupBase.cs
@@ -0,0 +1,14 @@
+using AyCode.Interfaces.Entities;
+using AyCode.Interfaces.TimeStampInfo;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace AyCode.Interfaces.Groups
+{
+    public interface IGroupBase : IEntity, ITimeStampInfo
+    {
+    }
+}
diff --git a/AyCode.Interfaces/Messages/IMessageSenderService.cs b/AyCode.Interfaces/Messages/IMessageSenderService.cs
index c201675..935db68 100644
--- a/AyCode.Interfaces/Messages/IMessageSenderService.cs
+++ b/AyCode.Interfaces/Messages/IMessageSenderService.cs
@@ -4,6 +4,6 @@ namespace AyCode.Interfaces.Messages
 {
     public interface IMessageSenderService
     {
-        public Task<bool> SendMessageAsync(IMessageBase message, int[] messageTypes);
+        public Task<string> SendMessageAsync<TNotice>(TNotice message, int messageType) where TNotice : class, INoticeBase;
     }
 }
diff --git a/AyCode.Interfaces/Messages/IMessageBase.cs b/AyCode.Interfaces/Messages/INoticeBase.cs
similarity index 58%
rename from AyCode.Interfaces/Messages/IMessageBase.cs
rename to AyCode.Interfaces/Messages/INoticeBase.cs
index 93aacb6..fbf648c 100644
--- a/AyCode.Interfaces/Messages/IMessageBase.cs
+++ b/AyCode.Interfaces/Messages/INoticeBase.cs
@@ -5,8 +5,8 @@ using AyCode.Interfaces.TimeStampInfo;
 
 namespace AyCode.Interfaces.Messages
 {
-    public interface IMessageBase : IEntityGuid, ITimeStampInfo, IMessageParticipants
+    public interface INoticeBase : IEntityGuid, ITimeStampInfo, IMessageParticipants
     {        
-        string Message { get; }
+        string Message { get; }      
     }
 }
diff --git a/AyCode.Interfaces/ServiceProviders/IServiceProviderBase.cs b/AyCode.Interfaces/ServiceProviders/IServiceProviderBase.cs
new file mode 100644
index 0000000..ad96ff2
--- /dev/null
+++ b/AyCode.Interfaces/ServiceProviders/IServiceProviderBase.cs
@@ -0,0 +1,11 @@
+
+using AyCode.Interfaces.Entities;
+using AyCode.Interfaces.TimeStampInfo;
+
+namespace AyCode.Interfaces.ServiceProviders;
+
+public interface IServiceProviderBase : IEntityGuid, ITimeStampInfo
+{
+    string Name { get; }
+    Guid OwnerId { get; }
+}
\ No newline at end of file
diff --git a/AyCode.Models/Enums/PermissionContextMappingSubjectType.cs b/AyCode.Models/Enums/PermissionContextMappingSubjectType.cs
new file mode 100644
index 0000000..f945fb7
--- /dev/null
+++ b/AyCode.Models/Enums/PermissionContextMappingSubjectType.cs
@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace AyCode.Models.Enums
+{
+    
+    public enum PermissionContextMappingSubjectType
+    {
+        User = 1,
+        Group = 2
+    }
+}
diff --git a/AyCode.Models/Messages/EMailMessage.cs b/AyCode.Models/Messages/EMailMessage.cs
index cced456..ff77a17 100644
--- a/AyCode.Models/Messages/EMailMessage.cs
+++ b/AyCode.Models/Messages/EMailMessage.cs
@@ -7,12 +7,12 @@ using System.Threading.Tasks;
 
 namespace AyCode.Models.Messages
 {
-    public class EMailMessage : MessageBase
+    public class EmailMessage : NoticeBase
     {
-        public EMailMessage() { }        
+        public EmailMessage() { }        
         public string Subject { get; set; }
         public string HtmlContent { get; set; }
-        public EMailMessage(Guid senderId, Guid receiverId, string message, string subject, string htmlContent) : base(senderId, receiverId, message )
+        public EmailMessage(Guid senderId, Guid receiverId, string message, string subject, string htmlContent) : base(senderId, receiverId, message )
         {
             Subject = subject;
             HtmlContent = htmlContent;