In security engineering, there are many counter-intuitive phenomena:

for example I am happy (more or less) to use online banking every day,

where if something goes wrong, I can potentially lose a lot of money,

but I am staunchly against using electronic voting (lets call it

e-voting for short). E-voting is an idea that is nowadays often

promoted in order to counter low turnouts in elections\footnote{In my

  last local election where I was eligible to vote only 48\% of the

  population have cast their ballot. I was, I shamefully admit, one of

  the non-voters.} and generally sounds like a good idea. Right?

Voting from the comfort of your own home, or on your mobile on the go,

what could possibly go wrong? Even the UK's head of the Electoral

Commission, Jenny Watson, argued in 2014 in a Guardian article that

the UK should have e-voting. Her plausible argument is that 76\% of

pensioners in the UK vote (in a general election?), but only 44\% of

the under-25s. For which constituency politicians might therefore make

more favourable (short-term) decisions is clear. So being not yet

Well, it turns out there are many things that can go wrong with

e-voting, as I like to argue in this handout. E-voting in a ``secure

way'' seems to be one of the things in computer science that are still

very much unsolved. It is not on the 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 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 controversial topic in many

countries:

  machines, but ``hacktivists'' had found they can be hacked to change

  votes and also emitted radio signals revealing how you voted.

\item Germany conducted pilot studies with e-voting, but in 2007 a law

  suit has reached the highest court and it rejected e-voting on the

  grounds of not being understandable by the general public.

\item UK used optical scan voting systems in a few trail polls, but to

  my knowledge does not use any e-voting in elections.

\item The US used mechanical machines since the 1930s, later punch

  cards, now DREs and optical scan voting machines.

  elections. There were earlier pilot studies for voting via Internet

  in other countries.

\item India uses e-voting devices since at least 2003. They used

  ``keep-it-simple'' machines produced by a government owned company.

  elections (when Nelson Mandela was elected) and found that the

  tallying software was rigged, but they were able to tally manually.

The reason that e-voting is such a hard problem is that we have

requirements about the voting process that conflict with each

other. The five main requirements for voting in general are:

  \item (Stronger) Even if you try, you cannot prove how you

    voted. The reason is that you want to avoid vote selling as has

    been tried, for example, by a few jokers in the recent 

    Scottish referendum.    

  \item Only authorised voters can vote up to the permitted number of votes

    (in order to avoid the ``vote early, vote often'').