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\begin{document}
\raggedright
\footnotesize
\begin{multicols*}{4}
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\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}