  Constrained devices in IoT networks often require to outsource resource-heavy
computations or data processing tasks. Currently, most of those jobs are done
in the centralised cloud. However, with rapidly increasing number of devices
and amount of produced data, edge computing represents a much more efficient
solution decreasing the cost, the delay and improves users' privacy. To enable
wide deployment of execution nodes at the edge, the requesting devices require
a way to pay for submitted tasks. We present SPOC - a secure payment system for
networks where nodes distrust each other. SPOC allows any node to execute
tasks, includes result verification and enforce users' proper behaviour without
3rd parties, replication or costly proof of computations. We implement our
system using Ethereum Smart Contracts and Intel SGX and present first
evaluation proving its security and low usage cost.
