--- a/handouts/ho02.tex	Fri Oct 03 16:04:49 2014 +0100
+++ b/handouts/ho02.tex	Fri Oct 03 16:10:50 2014 +0100
@@ -33,7 +33,7 @@
 scale of Turing's halting problem, which is proved that it can
 never be solved in general, but more in the category of being
 unsolvable with current technology. This is not just my
-opinion, but also shared by many security researchers amogst
+opinion, but also shared by many security researchers amongst
 them Alex Halderman, who is the world-expert on this subject
 and from whose course on Securing Digital Democracy I have
 most of my information and inspiration. It is also a
@@ -95,7 +95,7 @@
         defended against. The problem with this is that if
         the incentives are great and enough resources are
         available, then maybe it is feasible to mount a DoS
-        attack agains voting server and by bringing the
+        attack against voting server and by bringing the
         system to its knees, change the outcome of an
         election. Not to mention to hack the complete
         system with malware and change votes undetectably.                
@@ -139,7 +139,7 @@
   \begin{itemize}
   \item The voting system should accept all authorised votes
         and produce results in a timely manner. If you move
-        an election online, you have to guard agains DoS 
+        an election online, you have to guard against DoS 
         attacks for example.
    \end{itemize}
 \end{itemize}
@@ -176,13 +176,13 @@
 were mainly based on voting by show of hands. While this
 method of voting satisfies many of the requirements stipulated
 above, the main problem with hand voting is that it does not
-guaranty ballot secrecy. As far as I know the old greeks and
-romans did not perceive this as a problem, but the result was
+guaranty ballot secrecy. As far as I know the old Greeks and
+Romans did not perceive this as a problem, but the result was
 that their elections favoured rich, famous people who had
 enough resources to swing votes. Even using small coloured
 stones did not really mitigate the problem with ballot
 secrecy. The problem of authorisation was solved by friends or
-neighbours vouching for you to prove you are elegible to vote
+neighbours vouching for you to prove you are eligible to vote
 (there were no ID cards in ancient Greece and Rome).
 
 Starting with the French Revolution and the US constitution,
@@ -265,7 +265,7 @@
 incompetency and inferiority of their products, by requiring
 that election counties must not give the machines up for
 independent review. They also kept their source secret. 
-This meant Halderman and his group had to obatain a machine
+This meant Halderman and his group had to obtain a machine
 not in the official channels. Then they had to reverse 
 engineer the source code in order to design their attack. 
 What this all showed is that a shady security design is no 
@@ -307,7 +307,7 @@
 India. Essentially they designed a bespoke voting device,
 which could not be used for anything else. Having a bespoke
 device is a good security engineering decision because it
-makes the attack surface smaller. If you have a fullfledged
+makes the attack surface smaller. If you have a full-fledged
 computer behind your system, then you can do everything a
 computer can do\ldots{}that is a lot, including a lot of
 abuse. What was bad that these machines did not have the
@@ -353,7 +353,7 @@
 able to covertly manipulate results by inserting malware on
 the voters' computers. Overall, their recommendation is 
 to abandon Internet voting and to go back to an entirely
-paper-based voting process. In face of state-sponsered
+paper-based voting process. In face of state-sponsored
 cyber-crime (for example NSA), Internet voting cannot be made
 secure with current technology. They have a small video
 clip with their findings at
@@ -401,7 +401,7 @@
 sophisticated process called \emph{zero-knowledge-proofs}.
 They essentially allow one to convince somebody else to know
 a secret without revealing what the secret is. This is a kind
-of cryptographiv ``magic'', like the Hellman-Diffie protocol
+of cryptographic ``magic'', like the Hellman-Diffie protocol
 which can be used to establish a secret even if you can only
 exchange postcards with your communication partner. We will
 look at zero-knowledge-proofs in a later lecture in more