Dealing with spam involves more than the annoying ritual of deleting unwanted emails. It imposes real costs in terms of time and money. Stopping spam requires both costly countermeasures by Internet service providers (ISPs) and the installation of filters that sometimes block wanted emails. Challenge-and-response systems work, but they don’t stop the phenomenon of emails ricocheting throughout the Internet, and create a few problems of their own. CEI supports efforts to detect spam and holding the senders of fraudulent email accountable. However, CEI believes that heavy government involvement in the process of authentication and accreditation would harm the interests of those desiring to prevent spam. Private mechanisms are most appropriate for private networks, where problems go well beyond spam to cybersecurity itself. Private authentication mechanisms also have a role to play in protecting intellectual property—a fact that may not be taken into account, or poorly addressed, in government certification of email.