chg: [workshop] LEA and encryption
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@ -77,6 +77,7 @@
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\item {\bf In-transit encryption}: protects data while it is
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transferred from one machine to another,
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\item {\bf At-rest encryption}: protects data stored on one machine.
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%\item {\bf Perfect Forward Secrecy}
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\end{itemize}
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\end{frame}
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@ -217,10 +218,6 @@ codebook to crack it.
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\begin{frame}
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\frametitle{Randomness}
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For instance AES-ECB is not semantically secure - An attacker can build a
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codebook to crack it.
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No Semantic Security without randomness
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\begin{itemize}
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\item
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\end{itemize}
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@ -229,7 +226,6 @@ codebook to crack it.
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\begin{frame}
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\frametitle{Generating Randomness}
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@ -255,6 +251,16 @@ codebook to crack it.
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\end{frame}
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\begin{frame}
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\frametitle{Type of encryption}
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\begin{itemize}
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\item
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\end{itemize}
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\end{frame}
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\begin{frame}
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\frametitle{How thinks can go wrong}
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Some attacks requires less than CCA / CPA:
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@ -264,6 +270,95 @@ codebook to crack it.
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\end{frame}
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\begin{frame}
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\begin{center}
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{\bf Encryption and Law Enforcement}
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\end{center}
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\end{frame}
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\begin{frame}
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\frametitle{2016 ENISA / EUROPOL joint statement}
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\begin{itemize}
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\item In the arms race between cryptographers and crypto-analysts. In
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terms of practical breaks, cryptographers are miles ahead.
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\item In a society that is ever more depending on the correct
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functioning of electronic communication services, technical
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protection of these service is mandatory,
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\item In the face of serious crimes, law enforcement may lawfully
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intrude privacy or break into security mechanisms of electronic communication,
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\item {\bf proportionality} - collateral damages (class breaks)
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\item Resolving the encryption dilemma: collect and share best
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practices to circumvent encryption.
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\end{itemize}
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\end{frame}
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\begin{frame}[allowframebreaks]
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\frametitle{Encryption Workarounds~\cite{kerr2017}}
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\begin{quote}
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Any effort to reveal an unencrypted version of a target's data that
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has been concealed be encryption.
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\end{quote}
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\begin{itemize}
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\item Try to get the key:
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\begin{itemize}
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\item {\bf Find the key:}
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\begin{itemize}
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\item physical searches for keys,
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\item password managers,
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\item web browser password database,
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\item in-memory copy of the key in computer's HDD / RAM.
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\item seize the key (keylogger).
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\end{itemize}
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\item {\bf Guess the key:},
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\begin{itemize}
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\item Whereas encryption keys are usually too hard to guess (but more on that
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later...),
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\item passphrases are usually shorter to be memorizable, and are
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linked to the key,
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\item some systems have limitations on sorts of passwords (eg. 4/6
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digits banking application),
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\item educated guess on the password from context,
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\item educated guess from owner's other passwords,
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\item dictionaries and password generation rules (\footnote{\url{https://hashcat.net/hashcat/}}).
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\item Offline / online attacks (eg. 13 digits pw: 25.000 on an
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iphone VS matter of minutes offline),
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\item + beware devices protection when online (eg. iphone erase on failure).
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\end{itemize}
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\item {\bf Compel the key:}
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\begin{figure}
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\centering
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\includegraphics[width=180px]{security.png}
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\end{figure}
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\end{itemize}
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\item Try to access the PlaintText without the key:
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\begin{itemize}
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\item Exploit a Flaw,
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\item Access Plaintext when in use,
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\item Locate Plaintext copy
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\end{itemize}
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\end{itemize}
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{\bf No workaround works every time.}
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\framebreak
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In short, crypto-systems have weaknesses:
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\begin{itemize}
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\item key generation,
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\item key length,
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\item key distribution,
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\item key storage,
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\item how users enter keys into the crypto-system,
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\item weakness in the algorithm itself / implementation,
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\item system / computer running the algorithm,
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\item crypto system used in different points in time,
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\item {\bf users.}
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\end{itemize}
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\end{frame}
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@ -118,4 +118,21 @@
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url = {https://www.usenix.org/conference/usenixsecurity14/technical-sessions/presentation/yarom},
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}
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@TechReport{europol19,
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author = {Joint Reports},
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title = {{{First report of the observatory function on encryption}}},
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institution = {EUROPOL - EC3},
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year = {2019},
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}
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@Article{kerr2017,
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author = {Orin S. Kerr and Bruce Schneier},
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title = {Encryption Workarounds},
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journal = {{SSRN} Electronic Journal},
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year = {2017},
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doi = {10.2139/ssrn.2938033},
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publisher = {Elsevier {BV}},
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url = {https://doi.org/10.2139/ssrn.2938033},
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}
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@Comment{jabref-meta: databaseType:bibtex;}
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