Counting Votes with Formal Methods

Since the late 1990s voting in the Netherlands proceeds largely via voting machines. These are dedicated computers that record and store votes. These machines are under control of local governments, who put them up in voting stations on election days. These voting machines (and all new versions of them) have undergone independent evaluation before being admitted. However the internal mechanics is secret. Also, the evaluation reports are not public. Nevertheless, at the time of introduction, these machines were uncontroversial. They have been used in several elections, without causing problems. Currently, such machines are the subject of much discussion, see for instance [2]. In 2002 the parliament of the Netherlands adopted a temporary law that went a step further than voting via computers at voting stations. The law allows experimentation with what is called location-independent voting. It has resulted in plans to allow voting via internet and phone in the 2004 elections for the European Parliament. This involves a one-time, limited experiment, largely intended to explore the possibilities and to gather experience with the required techniques and procedures.