some minor talk flow additions

talk-slides.tex

@@ -178,7 +178,7 @@ communication}
 
   \begin{itemize}
    \item \textbf{E}uropean \textbf{T}elecommunications \textbf{S}tandards \textbf{I}nstitute
-   \item network technologies used in middle layers:
+   \item this survey: focus on network technologies used in middle layers:
       \begin{itemize}
        \item GeoNetworking for geographical routing
        \item BTP as transport protocol
@@ -202,7 +202,6 @@ communication}
  \begin{itemize}
   \item problem: constant communication allows tracking of vehicles
   \item \textit{linkability} of messages threat to \textit{location privacy}
-  \item this survey: focus on middle network layers
   \item linkable identifiers in messages:
     \begin{itemize}
      \item vehicle position
@@ -249,11 +248,11 @@ communication}
      \item other nodes present for ambiguity
      \item coordinated change
      \item random change frequency
-     \item all identifiers changed simulataneously, buffers flushed
+     \item all identifiers changed simultaneously, buffers flushed
     \end{itemize}
   \item Car-2-Car CC: divide trips into 3 segments
-  \item Mix Zones
   \item Silent Periods
+  \item Mix Zones
  \end{itemize}
 
 \end{frame}
@@ -350,7 +349,7 @@ communication}
 
 \begin{frame}
  
- \center\huge{Thank you for your attention}
+ \center\huge{Thank you for your attention!}
  
  \includegraphics[height=0.5\textheight]{figures/nomnompingu.png}\tiny\footnote{CC-BY-SA 3.0 by Elektroll}
  

talk_notes.md

@@ -0,0 +1,72 @@
+% notes ITS talk
+
+- quite a long title, so let's 1st talk about ITS before we get to the Pseudonym Schemes
+
+## ITS
+
+- road traffic is still dangerous part of our everyday lives
+- infrastructure assist safety
+- recent years: decrease of traffic deaths
+- probably also thanks to assistance systems
+    - currently working on their own
+- collaboration, proactively broadcast, communicate
+
+- multiple standardization groups working on it
+- survey focuses on middle layers
+- GN: geograhical ad-hoc routing, broadcast unicast multicast
+
+- constant communication, linkability
+- location privacy: deriving location patterns of a single user
+- authorized senders: message signing
+
+## pseudonym schemes
+
+- proposed solution: pseudonyms
+    - must not be linkable
+- we only want authorized vehicles to communicate
+
+- a priori trusted: RootCA
+- EA knows vehicle ID & public key
+- AA trusts valid EA certificates
+- pseudonym resolution: desirable for law enforcement agencies
+
+## pseudonym change
+
+- many strategies have been proposed
+- C2C CC: statistical values:
+    - shall achieve that locations significant to a user can't be linked together nor to the user
+    - 0.8-1.5km, then each 0.8km or 2-6min
+- vehicle-centric change strategies: depending on mobility, trajectory
+- density-based
+- cryptographic mix zones: symm. key from RSU
+    - safety of collision avoidance systems
+
+### advanced schemes
+
+- identity-based:
+    - advantage: no certificates needed as ID = key
+    - disadvantage: splitting mapping information hard, Trusted Authority involved in key derivation
+- group signature:
+    - all members of group can sign for same public key
+    - problems: group leader, group change -> re-setup of all group keys
+- symmetric MACs:
+    - less computation overhead
+    - but not really practically usable, as signature checking is done by 3rd parties
+
+## attacker model
+
+- single-point:
+    - communication with EA and AA encrypted, C2C 3 segments (reception range)
+    - no cooperative change needed
+- global passive:
+    - cooperative change
+    - cryptographic mix zones sufficient
+- active: pseudonym depeltion
+- active insider:
+    - real silent periods needed, crypto mix zones don't work anymore
+    - servers in the internet can't link IPv6 address thanks to stateless autoconfiguration
+- special attacks:
+    - pseudonym depletion attack
+    - sybil attack
+- privileged: accountability, resolution
+    -  needs independent judicial systems and separation of powers