discussion points and summary

talk-slides.tex

@@ -349,6 +349,7 @@ based on Chord
   \item relay instance verifies incoming post's signature, then relays post URI (ID) to all subscribers + storage node\note[item]{only post ID relayed, but not full post content. Reasons: LDSignatures not supported everywhere, deniability \& revocation}
   \item subscribing instances can now retrieve the full authenticated post from received post URI
  \end{enumerate}
+ \note[item]{for joining and leaving the DHT see paper}
 
 \end{frame}
 
@@ -391,6 +392,7 @@ distribution of posts per hashtag follows a steep power law
   \item nodes have a \textbf{capacity} and choose set of active IDs according to lowest mismatch of own and neighbour node capacity
   \item querying load of potential IDs before joining, periodic re-balancing
   \item independent load balancing of relay and storage nodes due to independent DHTs
+  \note[item]{a simple simulation on the effectivity of the balancing algorithm can be found in the paper}
  \end{itemize}
 % for Kolloquium, add simulation result
 \end{frame}
@@ -413,10 +415,6 @@ distribution of posts per hashtag follows a steep power law
 \end{frame}
 
 
-
-why even still use classic push federation?
-
-
 \section{Discussion}
 
 \begin{frame}{Discussion}{I need YOUR feedback}
@@ -427,15 +425,85 @@ I want feedback from all of you, no matter whether it's from a \textit{\LARGE te
 
 \subsection{Social Considerations}
 
+\begin{frame}{Social Considerations}
+Do we even want global hashtags in the Fediverse?
+
+\begin{itemize}
+ \item positive potential (conversation, coordination) vs. negative potential (spam, harrasment)
+ \item visibility level: public posts only, unlisted, new level necessary?
+ \item relaying post URI only should provide plausible deniability
+ \item Does this circumvent instance-blocks and is this bad?
+\end{itemize}
+\end{frame}
+
+
 \subsection{Technical Considerations}
 
-CloudFlare
+\begin{frame}{Technical Considerations}{instance admins}
+ 
+\begin{itemize}
+ \item intended as opt-in, domain-based push federation still better for user subscriptions
+ \item assumption: instances offer \(5.5\times\) the storage \& \(2.5\times\) the bandwith of own posts
+ \item performance: Can this be implemented efficiently enough to not DDoS popular hashtag nodes?
+ \begin{itemize}
+  \item batched retrieval of posts from same source
+  \item exponential backoff retries
+ \end{itemize}
+\end{itemize}
+\end{frame}
+
+\begin{frame}{Technical Considerations}{integration into the ActivityPub Fediverse}
+ \begin{itemize}
+  \item This architecture is an unimplemented concept so far!
+  \item integration into ActivityPub ecosystem\note[item]{disclaimer: I'm new to ActivityPub and have no implementation experience}
+  \begin{itemize}
+   \item hashtags may be represented as relay actors with own in- \& outbox, addressed in cc
+   \item relaying to subscribers via SharedInbox
+   \item idea for addressing: new URI scheme that gets transparently resolved to responsible node's domain via DHT\note[item]{application proxy for transparent URI scheme resolving?}
+   \item signalling of error codes and redundancy factors is needed
+  \end{itemize}
+ \item DHT routing communication does not use ActivityPub
+ \end{itemize}
+\end{frame}
+
+\begin{frame}{Technical Considerations}{node ID assignment}
 
-load and capacity factor
+\note[item]{Let's talk about the elephant in the room of ``federated services''}
+\centering
+\includegraphics<1>[height=0.59\paperheight]{figures/Elephant_Friend_(Greeting).png}
+\includegraphics<2,4>[height=0.59\paperheight]{figures/hist_num_single_vs.png}
 
-performance: batching, exponential back-off, no relayable sigs
+\note[item]{sorry to all instance admins, but: CloudFlare behaves like a MITM/ Sybil attacker}
+
+\only<2,4>{1st peak: Masto.host, 2nd peak: Cloudflare}
+
+\only<3>{{\ttfamily
+\(h_n =\) hash(IPv6\_addr[0,63] ++ vserver)[0,63] \\
+++ hash(domain ++ vserver)[0,127] \\
+++ hash(IPv6\_addr[0,63] ++ vserver)[64,127]
+}
+\vspace{2em}
+
+node ID derivation}
+
+\end{frame}
+
+\subsection{Security Considerations}
+\begin{frame}{Security Considerations}
+ \begin{itemize}
+  \item attacker shall not be able to deliberately gain responsibility for certain hashtags
+  \begin{itemize}
+   \item node ID mainly dependant on IPv6 subnet
+  \end{itemize}
+
+  \item attacker shall not introduce arbitrary number of nodes
+  \begin{itemize}
+   \item valid domain required for node ID derivation, assumption: domains cost money
+  \end{itemize}
+ \end{itemize}
+
+\end{frame}
 
-security: node ID derivation scheme
 
 \section{Summary}
 
@@ -444,15 +512,18 @@ security: node ID derivation scheme
   % Keep the summary *very short*.
   \begin{itemize}
   \item
-    things can be \alert{highlighted}.
+    decentralised architecture for handling posts of the same hashtag:
+    \begin{itemize}
+     \item \alert{subscribe to hashtag} and get posts \alert{relay}ed
+     \item \alert{query stored posts} of a certain hashtag without subscription
+    \end{itemize}
+  \item responsibility for hashtag divided among instances using a DHT
+  \item architecture \alert{balances the load} between nodes and maintains \alert{redundancy}
+  \item several open questions before implementation
   \end{itemize}
   
   % The following outlook is optional.
-  \vskip0pt plus.5fill
-  \begin{itemize}
-  \item
-    Outlook
-  \end{itemize}
+  %\vskip0pt plus.5fill
 \end{frame}
 
 
@@ -471,17 +542,18 @@ security: node ID derivation scheme
    
 \end{frame}
 
-\begin{frame}{Complete Paper}
-\center
- \includegraphics[height=0.45\paperheight]{figures/qr_paper.png}\\
- \url{https://git.orlives.de/schmittlauch/paper_hashtag_federation/src/branch/master/paper_hashtag_federation.pdf}
+\begin{frame}
+
+ \center\huge{Questions, comments, feedback?}
+ 
+ \includegraphics[height=0.4\paperheight]{figures/qr_paper.png}\\
+ \large\url{https://git.orlives.de/schmittlauch/paper_hashtag_federation/src/branch/master/paper_hashtag_federation.pdf}
  
 \end{frame}
 
 
 \begin{frame}
  
- \center\huge{Thank you for your attention!}
  
  %\includegraphics[height=0.5\textheight]{figures/nomnompingu.png}\tiny\footnote{CC-BY-SA 3.0 by Elektroll}