diff --git a/rdpy/protocol/network/type.py b/rdpy/protocol/network/type.py
index b74a119..a74c932 100644
--- a/rdpy/protocol/network/type.py
+++ b/rdpy/protocol/network/type.py
@@ -47,9 +47,10 @@ class SimpleType(Type):
     '''
     simple type
     '''
-    def __init__(self, structFormat, typeSize, value):
+    def __init__(self, structFormat, typeSize, signed, value):
         self._typeSize = typeSize
         self._structFormat = structFormat
+        self._signed = signed
         self.value = value
         
     @property
@@ -64,7 +65,7 @@ class SimpleType(Type):
         '''
         setter of value after check it
         '''
-        if self.__class__.__dict__.has_key("isInRange") and not self.__class__.isInRange(value):
+        if not self.isInRange(value):
             raise InvalidValue("value is out of range for %s"%self.__class__)
         self._value = value    
     
@@ -85,12 +86,69 @@ class SimpleType(Type):
         read value from stream
         '''
         self._value = struct.unpack(self._structFormat,s.read(self._typeSize))[0]
+    
+      
+    def mask(self):
+        '''
+        compute bit mask for type
+        beacause in python all numbers are int long or float
+        '''
+        if not self.__dict__.has_key("_mask"):
+            mask = 0xff
+            for i in range(1, self._typeSize):
+                mask = mask << 8
+                mask |= 0xff
+            self._mask = mask
+        return self._mask
+    
+    def isInRange(self, value):
+        '''
+        check if value is in mask range
+        '''
+        if self._signed:
+            return not (value < -(self.mask() >> 1) or value > (self.mask() >> 1))
+        else:
+            return not (value < 0 or value > self.mask())
         
     def __sizeof__(self):
         '''
         return size of type
         '''
         return self._typeSize
+    
+    def __invert__(self):
+        '''
+        implement not operator
+        '''
+        invert = ~self._value
+        if not self._signed:
+            invert &= self.mask()
+        return self.__class__(invert)
+    
+    def __add__(self, other):
+        '''
+        implement addition operator
+        '''
+        return self.__class__(self._value.__add__(other._value))
+    
+    def __sub__(self, other):
+        '''
+        implement sub operator
+        '''
+        return self.__class__(self._value.__sub__(other._value))
+    
+    def __and__(self, other):
+        '''
+        implement bitwise and operator
+        '''
+        return self.__class__(self._value.__and__(other._value))
+    
+    def __or__(self, other):
+        '''
+        implement bitwise and operator
+        '''
+        return self.__class__(self._value.__or__(other._value))
+
         
 class CompositeType(Type):
     '''
@@ -107,7 +165,7 @@ class CompositeType(Type):
         '''
         magic function to update type list
         '''
-        if name[0] != '_' and (isinstance(value, Type) or isinstance(value, tuple)):
+        if name[0] != '_' and (isinstance(value, Type) or isinstance(value, tuple)) and not self.__dict__.has_key(name):
             self._type.append(value)
         self.__dict__[name] = value
             
@@ -142,14 +200,17 @@ class UInt8(SimpleType):
         '''
         constructor check value range
         '''
-        SimpleType.__init__(self, "B", 1, value)
-        
-    @staticmethod
-    def isInRange(value):
+        SimpleType.__init__(self, "B", 1, False, value)
+
+class SInt8(SimpleType):
+    '''
+    unsigned byte
+    '''    
+    def __init__(self, value = 0):
         '''
-        return true if value is in UInt8 range
+        constructor check value range
         '''
-        return not (value < 0 or value > 0xff)
+        SimpleType.__init__(self, "b", 1, True, value)
         
         
 class UInt16Be(SimpleType):
@@ -160,14 +221,7 @@ class UInt16Be(SimpleType):
         '''
         constructor check value range
         '''
-        SimpleType.__init__(self, ">H", 2, value)
-        
-    @staticmethod
-    def isInRange(value):
-        '''
-        return true if value is in UInt8 range
-        '''
-        return not (value < 0 or value > 0xffff)
+        SimpleType.__init__(self, ">H", 2, False, value)
         
 class UInt16Le(SimpleType):
     '''
@@ -177,14 +231,7 @@ class UInt16Le(SimpleType):
         '''
         constructor check value range
         '''
-        SimpleType.__init__(self, "<H", 2, value)
-        
-    @staticmethod
-    def isInRange(value):
-        '''
-        return true if value is in UInt8 range
-        '''
-        return not (value < 0 or value > 0xffff)
+        SimpleType.__init__(self, "<H", 2, False, value)
         
 class UInt32Be(SimpleType):
     '''
@@ -194,14 +241,7 @@ class UInt32Be(SimpleType):
         '''
         constructor check value range
         '''
-        SimpleType.__init__(self, ">I", 4, value)
-        
-    @staticmethod
-    def isInRange(value):
-        '''
-        return true if value is in UInt8 range
-        '''
-        return not (value < 0 or value > 0xffffffff)
+        SimpleType.__init__(self, ">I", 4, False, value)
         
 class UInt32Le(SimpleType):
     '''
@@ -211,15 +251,8 @@ class UInt32Le(SimpleType):
         '''
         constructor check value range
         '''
-        SimpleType.__init__(self, "<I", 4, value)
+        SimpleType.__init__(self, "<I", 4, False, value)
     
-    @staticmethod
-    def isInRange(value):
-        '''
-        return true if value is in UInt8 range
-        '''
-        return not (value < 0 or value > 0xffffffff)
-        
 class SInt32Le(SimpleType):
     '''
     unsigned int with little endian representation
@@ -228,14 +261,7 @@ class SInt32Le(SimpleType):
         '''
         constructor check value range
         '''
-        SimpleType.__init__(self, "<I", 4, value)
-        
-    @staticmethod
-    def isInRange(value):
-        '''
-        return true if value is in UInt8 range
-        '''
-        return not (value < ~0x7fffffff or value > 0x7fffffff)
+        SimpleType.__init__(self, "<I", 4, True, value)
         
 class SInt32Be(SimpleType):
     '''
@@ -245,15 +271,8 @@ class SInt32Be(SimpleType):
         '''
         constructor check value range
         '''
-        SimpleType.__init__(self, ">I", 4, value)
+        SimpleType.__init__(self, ">I", 4, True, value)
         
-    @staticmethod
-    def isInRange(value):
-        '''
-        return true if value is in UInt8 range
-        '''
-        return not (value < ~0x7fffffff or value > 0x7fffffff)
-
 class UInt24Be(SimpleType):
     '''
     unsigned int with big endian representation
@@ -262,14 +281,7 @@ class UInt24Be(SimpleType):
         '''
         constructor check value range
         '''
-        SimpleType.__init__(self, ">I", 3, value)
-        
-    @staticmethod
-    def isInRange(value):
-        '''
-        return true if value is in UInt8 range
-        '''
-        return not (value < 0 or value > 0xffffff)
+        SimpleType.__init__(self, ">I", 3, False, value)
         
     def write(self, s):
         '''
@@ -291,14 +303,7 @@ class UInt24Le(SimpleType):
         '''
         constructor check value range
         '''
-        SimpleType.__init__(self, "<I", 3, value)
-    
-    @staticmethod
-    def isInRange(value):
-        '''
-        return true if value is in UInt8 range
-        '''
-        return not (value < 0 or value > 0xffffff)    
+        SimpleType.__init__(self, "<I", 3, False, value)   
             
     def write(self, s):
         '''
diff --git a/rdpy/protocol/rdp/ber.py b/rdpy/protocol/rdp/ber.py
index bc47c6b..4200d8b 100644
--- a/rdpy/protocol/rdp/ber.py
+++ b/rdpy/protocol/rdp/ber.py
@@ -1,14 +1,15 @@
 '''
 @author: sylvain
 '''
-from rdpy.protocol.network.type import UInt16Le
+from rdpy.protocol.network.type import UInt8, UInt16Be
 from rdpy.utils.const import ConstAttributes
+from rdpy.protocol.network.error import InvalidExpectedDataException
 
 @ConstAttributes
 class BerPc(object):
-    BER_PC_MASK = UInt16Le(0x20)
-    BER_PRIMITIVE = UInt16Le(0x00)
-    BER_CONSTRUCT = UInt16Le(0x20)
+    BER_PC_MASK = UInt8(0x20)
+    BER_PRIMITIVE = UInt8(0x00)
+    BER_CONSTRUCT = UInt8(0x20)
 
 def berPC(pc):
     '''
@@ -19,4 +20,33 @@ def berPC(pc):
         return BerPc.BER_CONSTRUCT
     else:
         return BerPc.BER_PRIMITIVE
-        
\ No newline at end of file
+    
+def readLength(s):
+    '''
+    read length of ber structure
+    length be on 1 2 or 3 bytes
+    '''
+    size = None
+    byte = UInt8()
+    s.readType(byte)
+    if (byte & UInt8(0x80)) == UInt8(0x80):
+        byte &= ~UInt8(0x80)
+        if byte == UInt8(1):
+            size = UInt8()
+        elif byte == UInt8(2):
+            size = UInt16Be()
+        else:
+            raise InvalidExpectedDataException("ber length may be 1 or 2")
+        s.readType(size)
+    else:
+        size = byte
+    return size
+
+def writeLength(size):
+    '''
+    write length as expected in Ber specification
+    '''
+    if size > UInt16Be(0x7f):
+        return (UInt8(0x82), size)
+    else:
+        return UInt8(size.value)
\ No newline at end of file
diff --git a/rdpy/protocol/rdp/per.py b/rdpy/protocol/rdp/per.py
new file mode 100644
index 0000000..8903756
--- /dev/null
+++ b/rdpy/protocol/rdp/per.py
@@ -0,0 +1,3 @@
+'''
+@author: sylvain
+'''
diff --git a/rdpy/protocol/rdp/tpdu.py b/rdpy/protocol/rdp/tpdu.py
index 6cab9fe..ee3f3e2 100644
--- a/rdpy/protocol/rdp/tpdu.py
+++ b/rdpy/protocol/rdp/tpdu.py
@@ -136,12 +136,10 @@ class TPDU(LayerAutomata):
         if negResp.len != UInt16Le(0x0008):
             raise InvalidExpectedDataException("invalid size of negotiation response")
         
-        protocol = negResp.protocol
-        if protocol != self._protocol:
-            raise NegotiationFailure("protocol negotiation failure")
+        self._protocol = negResp.protocol
         
-        #_transport is TPKT and transport is TCP layer of twisted
         if self._protocol == Protocols.PROTOCOL_SSL:
+            #_transport is TPKT and transport is TCP layer of twisted
             self._transport.transport.startTLS(ClientTLSContext())
         else:
             raise NegotiationFailure("protocol negociation failure")
diff --git a/rdpy/protocol/rfb/rfb.py b/rdpy/protocol/rfb/rfb.py
index 4c28143..9b58aa0 100644
--- a/rdpy/protocol/rfb/rfb.py
+++ b/rdpy/protocol/rfb/rfb.py
@@ -118,6 +118,7 @@ class Rfb(RawLayer):
         security handshake for 33 rfb version
         server imposed security level
         '''
+        #TODO!!!
         self._version = data.read_beuint32()