--- a/hws/hw06.tex	Sat Sep 23 19:32:21 2017 +0100
+++ b/hws/hw06.tex	Sat Sep 23 19:39:53 2017 +0100
@@ -9,25 +9,9 @@
 \HEADER
 
 \begin{enumerate}
-\item Explain briefly the purpose of the certification authority in
-  the public-private key encryption scheme.
-
-\item Explain briefly what is meant by a certification authority
-  becoming ``too big to fail'' when it has issued a large number 
-  of certificates.
-
-\item In which situations does it make sense to install
-  invalid (self-signed) certificates?
 
 
-%\item Zero-knowledge protocols depend on three main properties called
-%  completeness, soundness and zero-knowledge.  Explain what they mean?
 
-%\item Why do zero-knowledge protocols require an NP-problem as building
-%  block?
-
-%\item Why is it a good choice in a ZKP to flip a coin when requesting a 
-%  proof from the person who knows the secret?
 
 \item \POSTSCRIPT
 \end{enumerate}