diff --git a/common/rfb/SSecurityVncAuth.h b/common/rfb/SSecurityVncAuth.h
new file mode 100644
index 0000000..1d0a82d
--- /dev/null
+++ b/common/rfb/SSecurityVncAuth.h
@@ -0,0 +1,55 @@
+/* Copyright (C) 2002-2005 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.
+ */
+// SSecurityVncAuth - legacy VNC authentication protocol.
+// The getPasswd call can be overridden if you wish to store
+// the VncAuth password in an implementation-specific place.
+// Otherwise, the password is read from a BinaryParameter
+// called Password.
+
+#ifndef __RFB_SSECURITYVNCAUTH_H__
+#define __RFB_SSECURITYVNCAUTH_H__
+
+#include <rfb/SSecurity.h>
+#include <rfb/secTypes.h>
+#include <rdr/types.h>
+
+namespace rfb {
+
+  class VncAuthPasswdGetter {
+  public:
+    // getPasswd() returns a string or null if unsuccessful.  The
+    // SSecurityVncAuth object delete[]s the string when done.
+    virtual char* getVncAuthPasswd()=0;
+  };
+
+  class SSecurityVncAuth : public SSecurity {
+  public:
+    SSecurityVncAuth(VncAuthPasswdGetter* pg);
+    virtual bool processMsg(SConnection* sc);
+    virtual int getType() const {return secTypeVncAuth;}
+    virtual const char* getUserName() const {return 0;}
+  private:
+    enum {vncAuthChallengeSize = 16};
+    rdr::U8 challenge[vncAuthChallengeSize];
+    rdr::U8 response[vncAuthChallengeSize];
+    bool sentChallenge;
+    int responsePos;
+    VncAuthPasswdGetter* pg;
+  };
+}
+#endif