chg: [workshop] LEA and encryption

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Jean-Louis Huynen 2019-11-18 17:36:41 +01:00
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@ -77,6 +77,7 @@
\item {\bf In-transit encryption}: protects data while it is
transferred from one machine to another,
\item {\bf At-rest encryption}: protects data stored on one machine.
%\item {\bf Perfect Forward Secrecy}
\end{itemize}
\end{frame}
@ -217,10 +218,6 @@ codebook to crack it.
\begin{frame}
\frametitle{Randomness}
For instance AES-ECB is not semantically secure - An attacker can build a
codebook to crack it.
No Semantic Security without randomness
\begin{itemize}
\item
\end{itemize}
@ -229,7 +226,6 @@ codebook to crack it.
\begin{frame}
\frametitle{Generating Randomness}
@ -255,6 +251,16 @@ codebook to crack it.
\end{frame}
\begin{frame}
\frametitle{Type of encryption}
\begin{itemize}
\item
\end{itemize}
\end{frame}
\begin{frame}
\frametitle{How thinks can go wrong}
Some attacks requires less than CCA / CPA:
@ -264,6 +270,95 @@ codebook to crack it.
\end{frame}
\begin{frame}
\begin{center}
{\bf Encryption and Law Enforcement}
\end{center}
\end{frame}
\begin{frame}
\frametitle{2016 ENISA / EUROPOL joint statement}
\begin{itemize}
\item In the arms race between cryptographers and crypto-analysts. In
terms of practical breaks, cryptographers are miles ahead.
\item In a society that is ever more depending on the correct
functioning of electronic communication services, technical
protection of these service is mandatory,
\item In the face of serious crimes, law enforcement may lawfully
intrude privacy or break into security mechanisms of electronic communication,
\item {\bf proportionality} - collateral damages (class breaks)
\item Resolving the encryption dilemma: collect and share best
practices to circumvent encryption.
\end{itemize}
\end{frame}
\begin{frame}[allowframebreaks]
\frametitle{Encryption Workarounds~\cite{kerr2017}}
\begin{quote}
Any effort to reveal an unencrypted version of a target's data that
has been concealed be encryption.
\end{quote}
\begin{itemize}
\item Try to get the key:
\begin{itemize}
\item {\bf Find the key:}
\begin{itemize}
\item physical searches for keys,
\item password managers,
\item web browser password database,
\item in-memory copy of the key in computer's HDD / RAM.
\item seize the key (keylogger).
\end{itemize}
\item {\bf Guess the key:},
\begin{itemize}
\item Whereas encryption keys are usually too hard to guess (but more on that
later...),
\item passphrases are usually shorter to be memorizable, and are
linked to the key,
\item some systems have limitations on sorts of passwords (eg. 4/6
digits banking application),
\item educated guess on the password from context,
\item educated guess from owner's other passwords,
\item dictionaries and password generation rules (\footnote{\url{https://hashcat.net/hashcat/}}).
\item Offline / online attacks (eg. 13 digits pw: 25.000 on an
iphone VS matter of minutes offline),
\item + beware devices protection when online (eg. iphone erase on failure).
\end{itemize}
\item {\bf Compel the key:}
\begin{figure}
\centering
\includegraphics[width=180px]{security.png}
\end{figure}
\end{itemize}
\item Try to access the PlaintText without the key:
\begin{itemize}
\item Exploit a Flaw,
\item Access Plaintext when in use,
\item Locate Plaintext copy
\end{itemize}
\end{itemize}
{\bf No workaround works every time.}
\framebreak
In short, crypto-systems have weaknesses:
\begin{itemize}
\item key generation,
\item key length,
\item key distribution,
\item key storage,
\item how users enter keys into the crypto-system,
\item weakness in the algorithm itself / implementation,
\item system / computer running the algorithm,
\item crypto system used in different points in time,
\item {\bf users.}
\end{itemize}
\end{frame}

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@ -118,4 +118,21 @@
url = {https://www.usenix.org/conference/usenixsecurity14/technical-sessions/presentation/yarom},
}
@TechReport{europol19,
author = {Joint Reports},
title = {{{First report of the observatory function on encryption}}},
institution = {EUROPOL - EC3},
year = {2019},
}
@Article{kerr2017,
author = {Orin S. Kerr and Bruce Schneier},
title = {Encryption Workarounds},
journal = {{SSRN} Electronic Journal},
year = {2017},
doi = {10.2139/ssrn.2938033},
publisher = {Elsevier {BV}},
url = {https://doi.org/10.2139/ssrn.2938033},
}
@Comment{jabref-meta: databaseType:bibtex;}