Internet security despite untrustworthy agents and components

As an Internet user, the security of your communications relies on a large number of agents: your own computer, its operating system, its Internet software (e.g. your web browser), your modem, telephone line, telephone company, ISP and their operators, computers, software, the DNS infrastructure, the links interconnecting the ISPs and the companies operating these links, the ISP of your correspondent (e.g. a web server), the hardware and the software run by this correspondent. Each of these agents are more or less likely to be hostile, and/or vulnerable to security attacks. The paper discusses the deliquescence of trust and considers some trustworthy Internet services