This chapter explores security in the context of electronic communication. Firstly, a definition of information security will be given. Secondly, the method of threat assessment will be introduced, which allows the determination of the level of security that is sufficient for a given application (e.g. communications between parties and the arbitral tribunal). Thirdly, specific security requirements will be provided for each type of potential attacker in a specific context. This consists of basic security hygiene measures that are necessary for individuals accessing the Internet, followed by more specific requirements for law offices. The last part of this chapter introduces a blueprint for secure infrastructure suited for e-arbitration that is defendable against the most sophisticated adversaries.1