  Over the last decade, the cloud computing landscape has transformed from a
centralised architecture made of large data centres to a distributed and
heterogeneous architecture embracing edge and IoT units. This shift has created
the so-called cloud-edge continuum, which closes the gap between large data
centres and end-user devices. Existing solutions for programming the continuum
are, however, dominated by proprietary silos and incompatible technologies,
built around dedicated devices and run-time stacks. In this position paper, we
motivate the need for an interoperable environment that would run seamlessly
across hardware devices and software stacks, while achieving good performance
and a high level of security -- a critical requirement when processing data
off-premises. We argue that the technology provided by WebAssembly running on
modern virtual machines and shielded within trusted execution environments,
combined with a core set of services and support libraries, allows us to meet
both goals. We also present preliminary results from a prototype deployed on
the cloud-edge continuum.
