  While email is the most ubiquitous and interoperable form of online
communication today, it was not conceived with strong security guarantees, and
the ensuing security enhancements are, by contrast, lacking in both ubiquity
and interoperability. This situation motivates our research. We begin by
identifying a variety of stakeholders who have an interest in the current email
system and in efforts to provide secure solutions. We then use the tussle among
stakeholders to explain the evolution of fragmented secure email solutions
undertaken by industry, academia, and independent developers. We also evaluate
the building blocks of secure email -- cryptographic primitives, key management
schemes, and system designs -- to identify their support for stakeholder
properties. From our analysis, we conclude that a one-size-fits-all solution is
unlikely. Furthermore, we highlight that vulnerable users are not well served
by current solutions, account for the failure of PGP, and argue that secure
messaging, while complementary, is not a fully substitutable technology.
