diff --git a/.travis.yml b/.travis.yml
index f707463..e349468 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,7 +7,7 @@ before_install:
   - sudo apt-get install python-qt4
   - ln -s /usr/lib/python2.7/dist-packages/PyQt4/ $VIRTUAL_ENV/lib/python2.7/site-packages/
   - ln -s /usr/lib/python2.7/dist-packages/sip.so $VIRTUAL_ENV/lib/python2.7/site-packages/
-  - pip install qt4reactor pyopenssl twisted service_identity rsa
+  - pip install qt4reactor pyopenssl twisted service_identity rsa pyasn1
 
 install:
   - python setup.py install
diff --git a/README.md b/README.md
index 76edd06..4502a54 100644
--- a/README.md
+++ b/README.md
@@ -44,7 +44,7 @@ x86 | x86_64
 
 ```
 $ git clone https://github.com/citronneur/rdpy.git rdpy
-$ pip install twisted pyopenssl qt4reactor service_identity rsa
+$ pip install twisted pyopenssl qt4reactor service_identity rsa pyasn1
 $ python rdpy/setup.py install
 ```
 
diff --git a/rdpy/security/ntlm.py b/rdpy/security/ntlm.py
new file mode 100644
index 0000000..1bf83dc
--- /dev/null
+++ b/rdpy/security/ntlm.py
@@ -0,0 +1,81 @@
+#
+# Copyright (c) 2014-2015 Sylvain Peyrefitte
+#
+# This file is part of rdpy.
+#
+# rdpy 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 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+"""
+@summary: NTLM Authentication
+@see: https://msdn.microsoft.com/en-us/library/cc236621.aspx
+"""
+
+from rdpy.core.type import CompositeType, String, UInt8, UInt16Le, UInt24Le, UInt32Le
+
+class MajorVersion(object):
+    """
+    @see: https://msdn.microsoft.com/en-us/library/cc236654.aspx
+    @see: https://msdn.microsoft.com/en-us/library/a211d894-21bc-4b8b-86ba-b83d0c167b00#id29
+    """
+    WINDOWS_MAJOR_VERSION_5 = 0x05
+    WINDOWS_MAJOR_VERSION_6 = 0x06
+    
+class MinorVersion(object):
+    """
+    @see: https://msdn.microsoft.com/en-us/library/cc236654.aspx
+    @see: https://msdn.microsoft.com/en-us/library/a211d894-21bc-4b8b-86ba-b83d0c167b00#id30
+    """
+    WINDOWS_MINOR_VERSION_0 = 0x00
+    WINDOWS_MINOR_VERSION_1 = 0x01
+    WINDOWS_MINOR_VERSION_2 = 0x02
+    WINDOWS_MINOR_VERSION_3 = 0x03
+    
+class NTLMRevision(object):
+    """
+    @see: https://msdn.microsoft.com/en-us/library/cc236654.aspx
+    """
+    NTLMSSP_REVISION_W2K3 = 0x0F
+
+class Version(CompositeType):
+    """
+    @summary: Version structure as describe in NTLM spec
+    @see: https://msdn.microsoft.com/en-us/library/cc236654.aspx
+    """
+    def __init__(self):
+        self.ProductMajorVersion = UInt8(MajorVersion.WINDOWS_MAJOR_VERSION_6)
+        self.ProductMinorVersion = UInt8(MinorVersion.WINDOWS_MINOR_VERSION_2)
+        self.ProductBuild = UInt16Le()
+        self.Reserved = UInt24Le()
+        self.NTLMRevisionCurrent = UInt8(NTLMRevision.NTLMSSP_REVISION_W2K3)
+
+class NegotiateMessage(CompositeType):
+    """
+    @summary: Negotiate capability of NTLM Authentication
+    @see: https://msdn.microsoft.com/en-us/library/cc236641.aspx
+    """
+    def __init__(self):
+        CompositeType.__init__(self)
+        self.Signature = String("NTLMSSP\x00", constant = True)
+        self.MessageType = UInt32Le(0x00000001)
+        self.NegotiateFlags = UInt32Le()
+        self.DomainNameLen = UInt16Le()
+        self.DomainNameMaxLen = UInt16Le(self.DomainNameLen)
+        self.DomainNameBufferOffset = UInt32Le()
+        self.WorkstationLen = UInt16Le()
+        self.WorkstationMaxLen = UInt16Le(self.WorkstationLen)
+        self.WorkstationBufferOffset = UInt32Le()
+        self.Version = Version()
+        self.Payload = String()
+        
\ No newline at end of file