diff --git a/OpenSim/Services/GridService/GridService.cs b/OpenSim/Services/GridService/GridService.cs
index 68269402b6..5c55c0b473 100644
--- a/OpenSim/Services/GridService/GridService.cs
+++ b/OpenSim/Services/GridService/GridService.cs
@@ -34,6 +34,7 @@ using log4net;
 using OpenSim.Framework;
 using OpenSim.Framework.Console;
 using OpenSim.Data;
+using OpenSim.Server.Base;
 using OpenSim.Services.Interfaces;
 using GridRegion = OpenSim.Services.Interfaces.GridRegion;
 using OpenMetaverse;
@@ -50,6 +51,8 @@ namespace OpenSim.Services.GridService
         private static GridService m_RootInstance = null;
         protected IConfigSource m_config;
 
+        protected IAuthenticationService m_AuthenticationService = null;
+
         public GridService(IConfigSource config)
             : base(config)
         {
@@ -60,6 +63,14 @@ namespace OpenSim.Services.GridService
             if (gridConfig != null)
             {
                 m_DeleteOnUnregister = gridConfig.GetBoolean("DeleteOnUnregister", true);
+                
+                string authService = gridConfig.GetString("AuthenticationService", String.Empty);
+
+                if (authService != String.Empty)
+                {
+                    Object[] args = new Object[] { config };
+                    m_AuthenticationService = ServerUtils.LoadPlugin<IAuthenticationService>(authService, args);
+                }
             }
             
             if (m_RootInstance == null)
@@ -118,7 +129,13 @@ namespace OpenSim.Services.GridService
 
                 if ((rflags & OpenSim.Data.RegionFlags.Authenticate) != 0)
                 {
-                    // TODO: Authenticate the principal
+                    // Can we authenticate at all?
+                    //
+                    if (m_AuthenticationService == null)
+                        return false;
+
+                    if (!m_AuthenticationService.Verify(new UUID(region.Data["PrincipalID"].ToString()), regionInfos.Token, 30))
+                        return false;
 
                     return false;
                 }
diff --git a/OpenSim/Services/Interfaces/IGridService.cs b/OpenSim/Services/Interfaces/IGridService.cs
index cd27145ee7..6b6b34797a 100644
--- a/OpenSim/Services/Interfaces/IGridService.cs
+++ b/OpenSim/Services/Interfaces/IGridService.cs
@@ -159,6 +159,7 @@ namespace OpenSim.Services.Interfaces
         public byte Access;
         public int  Maturity;
         public string RegionSecret;
+        public string Token;
 
         public GridRegion()
         {
@@ -306,6 +307,7 @@ namespace OpenSim.Services.Interfaces
             kvp["access"] = Access.ToString();
             kvp["regionSecret"] = RegionSecret;
             kvp["owner_uuid"] = EstateOwner.ToString();
+            kvp["token"] = Token.ToString();
             // Maturity doesn't seem to exist in the DB
             return kvp;
         }
@@ -363,6 +365,9 @@ namespace OpenSim.Services.Interfaces
             if (kvp.ContainsKey("owner_uuid"))
                 EstateOwner = new UUID(kvp["owner_uuid"].ToString());
 
+            if (kvp.ContainsKey("token"))
+                Token = kvp["token"].ToString();
+
         }
     }
 
diff --git a/prebuild.xml b/prebuild.xml
index fbb782a750..284913a68c 100644
--- a/prebuild.xml
+++ b/prebuild.xml
@@ -1056,6 +1056,7 @@
       <Reference name="OpenSim.Services.Base"/>
       <Reference name="OpenSim.Services.Connectors"/>
       <Reference name="OpenSim.Data"/>
+      <Reference name="OpenSim.Server.Base"/>
       <Reference name="Nini.dll" />
       <Reference name="log4net.dll"/>