diff --git a/.gitignore b/.gitignore
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--- /dev/null
+++ b/.gitignore
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+*.aux
+*.log
+*.out
+*.pdf
diff --git a/cheatsheet.tex b/cheatsheet.tex
new file mode 100644
index 0000000..be99a56
--- /dev/null
+++ b/cheatsheet.tex
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+\documentclass[10pt,landscape]{article}
+\usepackage[ngerman]{babel}
+\usepackage{multicol}
+\usepackage{calc}
+\usepackage{ifthen}
+\usepackage[landscape]{geometry}
+\usepackage{amsmath,amsthm,amsfonts,amssymb}
+\usepackage{color,graphicx,overpic}
+\usepackage{hyperref}
+\usepackage[utf8]{inputenc}
+\usepackage{algpseudocode}
+
+% This sets page margins to .5 inch if using letter paper, and to 1cm
+% if using A4 paper. (This probably isn't strictly necessary.)
+% If using another size paper, use default 1cm margins.
+\ifthenelse{\lengthtest { \paperwidth = 11in}}
+    { \geometry{top=.5in,left=.5in,right=.5in,bottom=.5in} }
+    {\ifthenelse{ \lengthtest{ \paperwidth = 297mm}}
+        {\geometry{top=1cm,left=1cm,right=1cm,bottom=1cm} }
+        {\geometry{top=1cm,left=1cm,right=1cm,bottom=1cm} }
+    }
+
+% Turn off header and footer
+\pagestyle{empty}
+
+% Redefine section commands to use less space
+\makeatletter
+\renewcommand{\section}{\@startsection{section}{1}{0mm}%
+                                {-1ex plus -.5ex minus -.2ex}%
+                                {0.5ex plus .2ex}%x
+                                {\normalfont\large\bfseries}}
+\renewcommand{\subsection}{\@startsection{subsection}{2}{0mm}%
+                                {-1explus -.5ex minus -.2ex}%
+                                {0.5ex plus .2ex}%
+                                {\normalfont\normalsize\bfseries}}
+\renewcommand{\subsubsection}{\@startsection{subsubsection}{3}{0mm}%
+                                {-1ex plus -.5ex minus -.2ex}%
+                                {1ex plus .2ex}%
+                                {\normalfont\small\bfseries}}
+\makeatother
+
+% itemize with smaller skips
+\newenvironment{tightitemize}
+    {\begin{itemize}
+    \setlength{\itemsep}{2pt}
+    \setlength{\parskip}{0pt}
+    \setlength{\parsep}{0pt}}
+    {\end{itemize}}
+
+
+% Define BibTeX command
+\def\BibTeX{{\rm B\kern-.05em{\sc i\kern-.025em b}\kern-.08em
+    T\kern-.1667em\lower.7ex\hbox{E}\kern-.125emX}}
+
+% Don't print section numbers
+\setcounter{secnumdepth}{0}
+
+
+\setlength{\parindent}{0pt}
+\setlength{\parskip}{0pt plus 0.5ex}
+
+
+\begin{document}
+\raggedright
+\footnotesize
+\begin{multicols*}{4}
+% multicol parameters
+% These lengths are set only within the two main columns
+%\setlength{\columnseprule}{0.25pt}
+\setlength{\premulticols}{1pt}
+\setlength{\postmulticols}{1pt}
+\setlength{\multicolsep}{1pt}
+\setlength{\columnsep}{2pt}
+
+\begin{center}
+     \section*{KN CheatSheet}
+\end{center}
+\section{Security}
+    \subsection{Grundlagen}
+    \begin{tightitemize}
+        \item Confidentiality (Vertraulichkeit, Abhörsicherheit)
+        \item Message integrity
+        \item Authentication
+        \item Access and Availability
+    \end{tightitemize}
+        \subsubsection{Angriffsmöglichkeiten}
+            \begin{tightitemize}
+                \item Passiv:
+                \begin{tightitemize}
+                    \item Abhören
+                    \item Verkehr analysieren
+                \end{tightitemize}
+                \item Aktiv:
+                \begin{tightitemize}
+                    \item Modifikation
+                    \item Wiederholen
+                    \item Einfügen/Löschen
+                    \item DOS (Denial of Service)
+                    \item Identität vortäuschen
+                \end{tightitemize}
+            \end{tightitemize}
+    \subsection{Kryptographie}
+    %TODO: some basics about cryptography, add it if you need it
+        \subsection{Angriffe}
+            \begin{tightitemize}
+                \item ciphertext-only
+                \item known-plaintext
+                \item chosen-plaintext
+            \end{tightitemize}
+        \subsubsection{Techniken}
+            \begin{tightitemize}
+                \item Symmetrische Verfahren
+                \begin{tightitemize}
+                    \item Stromchiffren
+                    \item Blockchiffren
+                    \begin{tightitemize}
+                        \item Problem: großes Codebook\\
+                            $\rightarrow$ pseudozufällige Funktionen
+                        \item CBC: Cipher Block Chaining
+                        \begin{tightitemize}
+                            \item Initialisierungsvektor
+                        \end{tightitemize}
+                        \item AES / DES (Feistelchiffren)
+                        \item Idee: 3DES: DES 3x anwenden
+                    \end{tightitemize}
+                \end{tightitemize}
+                \item Asymmetrische Verfahren
+                \begin{tightitemize}
+                    \item Beispiel: RSA
+                    \item rechenaufwendig\\
+                        $\rightarrow$ Key mit RSA, dann AES
+                \end{tightitemize}
+            \end{tightitemize}
+    \subsection{Message integrity}
+        \begin{tightitemize}
+            \item Inhalt
+            \begin{tightitemize}
+                \item Hash
+                \begin{tightitemize}
+                    \item mit Shared Secret (Message Authentication Code MAC)
+                    \item keine end-point Authentication (könnte replay sein)
+                    \item Nonce: number only used once
+                \end{tightitemize}
+            \end{tightitemize}
+            \item Quelle
+            \begin{tightitemize}
+                \item Signatur
+                \begin{tightitemize}
+                    \item non-repudiation
+                    \item Man-in-the-middle
+                    \item Keys müssen bekannt sein
+                    \item Keys zertifizieren (CA, gegenseitig)
+                \end{tightitemize}
+            \end{tightitemize}
+            \item nicht replay
+            \item Reihenfolge
+        \end{tightitemize}
+    \subsection{E-Mail Sicherheit}
+        \begin{tightitemize}
+            \item Verschlüsseln (symmetrischer und public key) und Signieren (private key)
+        \end{tightitemize}
+    \subsection{SSL}
+        \begin{tightitemize}
+            \item benutzt in https
+            \item Nachfolger: TLS
+            \item bietet: Confidentiality, Authentication and Integrity
+        \end{tightitemize}
+\end{multicols*}
+\end{document}