Binary file hws/hw07.pdf has changed

--- a/hws/hw07.tex	Wed Aug 05 09:52:50 2015 +0200
+++ b/hws/hw07.tex	Wed Aug 19 13:01:53 2015 +0800
@@ -10,10 +10,34 @@
 
 \item What is meant by the notion \emph{forward privacy}?
 
-\item Imagine you have an completely `innocent' email message, 
-  like birthday wishes to your grandmother? Why should you
-  still encrypt this message and your grandmother take the
-    effort to decrypt it? 
+\item Imagine you have an completely `innocent' email message,
+      like birthday wishes to your grandmother? Why should you
+      still encrypt this message and your grandmother take the
+      effort to decrypt it? 
+
+\item One part of achieving privacy (but not the only one) is
+      to properly encrypt your conversations on the Internet.
+      But this is fiercely resisted by some spy agencies.
+      These agencies (and some politicians for that
+      matter) argue that, for example, ISIL's recruiters
+      broadcast messages on, say, Twitter, and get people to
+      follow them. Then they move potential recruits to
+      Twitter Direct Messaging to evaluate if they are a
+      legitimate recruit. If yes, they move them to an
+      encrypted mobile-messaging app. The spy agencies argue
+      that although they can follow the conversations on
+      Twitter, they ``go dark'' on the encrypted message
+      app. To counter this ``going-dark problem'', the spy
+      agencies push for the implementation of back-doors in
+      iMessage and Facebook and Skype and everything else UK
+      or US-made, which they can use eavesdrop on
+      conversations without the conversants' knowledge or
+      consent.\medskip
+   
+      What is the fallacy in the spy agencies going-dark
+      argument? (Hint: Think what would happen if the spy
+      agencies and certain politicians get their wish.)
+       
 \end{enumerate}
 \end{document}