diff --git a/rfb_win32/Security.h b/rfb_win32/Security.h
new file mode 100644
index 0000000..d92e314
--- /dev/null
+++ b/rfb_win32/Security.h
@@ -0,0 +1,198 @@
+/* Copyright (C) 2002-2004 RealVNC Ltd.  All Rights Reserved.
+ *    
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ * USA.
+ */
+
+// Security.h
+
+// Wrapper classes for a few Windows NT security structures/functions
+// that are used by VNC
+
+#ifndef __RFB_WIN32_SECURITY_H__
+#define __RFB_WIN32_SECURITY_H__
+
+#include <rdr/types.h>
+#include <rdr/Exception.h>
+#include <rfb_win32/Win32Util.h>
+#include <rfb_win32/TCharArray.h>
+
+#include <lmcons.h>
+#include <Accctrl.h>
+#include <aclapi.h>
+
+#include <list>
+
+namespace rfb {
+
+  namespace win32 {
+
+    struct Trustee : public TRUSTEE {
+      Trustee(const TCHAR* name,
+              TRUSTEE_FORM form=TRUSTEE_IS_NAME,
+              TRUSTEE_TYPE type=TRUSTEE_IS_UNKNOWN)
+      {
+        pMultipleTrustee = 0;
+        MultipleTrusteeOperation = NO_MULTIPLE_TRUSTEE;
+        TrusteeForm = form;
+        TrusteeType = type;
+        ptstrName = (TCHAR*)name;
+      }
+    };
+
+    struct ExplicitAccess : public EXPLICIT_ACCESS {
+      ExplicitAccess(const TCHAR* name,
+                     TRUSTEE_FORM type,
+                     DWORD perms,
+                     ACCESS_MODE mode,
+                     DWORD inherit=0)
+      {
+        Trustee = rfb::win32::Trustee(name, type);
+        grfAccessPermissions = perms;
+        grfAccessMode = mode;
+        grfInheritance = inherit;
+      }
+    };
+
+    // Helper class for building access control lists
+    struct AccessEntries {
+      AccessEntries() : entries(0), entry_count(0) {}
+      ~AccessEntries() {delete [] entries;}
+      void allocMinEntries(int count) {
+        if (count > entry_count) {
+          EXPLICIT_ACCESS* new_entries = new EXPLICIT_ACCESS[entry_count+1];
+          if (entries) {
+            memcpy(new_entries, entries, sizeof(EXPLICIT_ACCESS) * entry_count);
+            delete entries;
+          }
+          entries = new_entries;
+        }
+      }
+      void addEntry(const TCHAR* trusteeName,
+                    DWORD permissions,
+                    ACCESS_MODE mode)
+      {
+        allocMinEntries(entry_count+1);
+        ZeroMemory(&entries[entry_count], sizeof(EXPLICIT_ACCESS));
+        entries[entry_count] = ExplicitAccess(trusteeName, TRUSTEE_IS_NAME, permissions, mode);
+        entry_count++;
+      }
+      void addEntry(const PSID sid, DWORD permissions, ACCESS_MODE mode) {
+        allocMinEntries(entry_count+1);
+        ZeroMemory(&entries[entry_count], sizeof(EXPLICIT_ACCESS));
+        entries[entry_count] = ExplicitAccess((TCHAR*)sid, TRUSTEE_IS_SID, permissions, mode);
+        entry_count++;
+      }
+
+      EXPLICIT_ACCESS* entries;
+      int entry_count;
+    };
+
+    // Helper class for handling SIDs
+    struct Sid {
+      Sid() : sid(0) {}
+      Sid(PSID sid_) : sid(sid_) {}
+      ~Sid() {
+        if (sid) FreeSid(sid);
+      }
+      operator PSID() const {return sid;}
+      PSID operator=(const PSID sid_) {
+        if (sid) FreeSid(sid);
+        sid = sid_;
+      }
+
+      static PSID Administrators() {
+        PSID sid = 0;
+        SID_IDENTIFIER_AUTHORITY ntAuth = SECURITY_NT_AUTHORITY;
+        if (!AllocateAndInitializeSid(&ntAuth, 2,
+          SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_ADMINS,
+          0, 0, 0, 0, 0, 0,
+          &sid)) 
+          throw rdr::SystemException("Sid::Administrators", GetLastError());
+        return sid;
+      }
+      static PSID SYSTEM() {
+        PSID sid = 0;
+        SID_IDENTIFIER_AUTHORITY ntAuth = SECURITY_NT_AUTHORITY;
+        if (!AllocateAndInitializeSid(&ntAuth, 1,
+          SECURITY_LOCAL_SYSTEM_RID, 0, 0, 0, 0, 0, 0, 0,
+          &sid))
+          throw rdr::SystemException("Sid::SYSTEM", GetLastError());
+        return sid;
+      }
+
+    protected:
+      PSID sid;
+    };
+      
+    // Helper class for handling & freeing ACLs
+    struct AccessControlList : public LocalMem {
+      AccessControlList(int size) : LocalMem(size) {}
+      AccessControlList(PACL acl_=0) : LocalMem(acl_) {}
+      operator PACL() {return (PACL)ptr;}
+    };
+
+    // Create a new ACL based on supplied entries and, if supplied, existing ACL 
+    static PACL CreateACL(const AccessEntries& ae, PACL existing_acl=0) {
+      typedef DWORD (WINAPI *_SetEntriesInAcl_proto) (ULONG, PEXPLICIT_ACCESS, PACL, PACL*);
+#ifdef UNICODE
+      const char* fnName = "SetEntriesInAclW";
+#else
+      const char* fnName = "SetEntriesInAclA";
+#endif
+      DynamicFn<_SetEntriesInAcl_proto> _SetEntriesInAcl(_T("advapi32.dll"), fnName);
+      if (!_SetEntriesInAcl.isValid())
+        throw rdr::SystemException("CreateACL failed; no SetEntriesInAcl", ERROR_CALL_NOT_IMPLEMENTED);
+      PACL new_dacl;
+      DWORD result;
+      if ((result = (*_SetEntriesInAcl)(ae.entry_count, ae.entries, existing_acl, &new_dacl)) != ERROR_SUCCESS)
+        throw rdr::SystemException("SetEntriesInAcl", result);
+      return new_dacl;
+    }
+
+    // Helper class for memory-management of self-relative SecurityDescriptors
+    struct SecurityDescriptorPtr : LocalMem {
+      SecurityDescriptorPtr(int size) : LocalMem(size) {}
+      SecurityDescriptorPtr(PSECURITY_DESCRIPTOR sd_=0) : LocalMem(sd_) {}
+      PSECURITY_DESCRIPTOR takeSD() {return takePtr();}
+    };
+
+    // Create a new self-relative Security Descriptor, owned by SYSTEM/Administrators,
+    //   with the supplied DACL and no SACL.  The returned value can be assigned
+    //   to a SecurityDescriptorPtr to be managed.
+    static PSECURITY_DESCRIPTOR CreateSdWithDacl(const PACL dacl) {
+      SECURITY_DESCRIPTOR absSD;
+      if (!InitializeSecurityDescriptor(&absSD, SECURITY_DESCRIPTOR_REVISION))
+        throw rdr::SystemException("InitializeSecurityDescriptor", GetLastError());
+      Sid owner(Sid::SYSTEM());
+      if (!SetSecurityDescriptorOwner(&absSD, owner, FALSE))
+        throw rdr::SystemException("SetSecurityDescriptorOwner", GetLastError());
+      Sid group(Sid::Administrators());
+      if (!SetSecurityDescriptorGroup(&absSD, group, FALSE))
+        throw rdr::SystemException("SetSecurityDescriptorGroupp", GetLastError());
+      if (!SetSecurityDescriptorDacl(&absSD, TRUE, dacl, FALSE))
+        throw rdr::SystemException("SetSecurityDescriptorDacl", GetLastError());
+      DWORD sdSize = GetSecurityDescriptorLength(&absSD);
+      SecurityDescriptorPtr sd(sdSize);
+      if (!MakeSelfRelativeSD(&absSD, sd, &sdSize))
+        throw rdr::SystemException("MakeSelfRelativeSD", GetLastError());
+      return sd.takeSD();
+    }
+
+  }
+
+}
+
+#endif