There is a rich recent literature on how to assist secure communication between a single transmitter and receiver
at the physical layer of wireless networks through techniques such as cooperative jamming. In this paper, we consider
how these single-hop physical layer security techniques can be extended to multi-hop wireless networks and show
how to augment physical layer security techniques with higher layer network mechanisms such as coding and
routing. Specifically, we consider the secure minimum energy routing problem, in which the objective is to compute
a minimum energy path between two network nodes subject to constraints on the end-to-end communication secrecy
and goodput over the path. This problem is formulated as a constrained optimization of transmission power and
link selection, which is proved to be NP-hard. Nevertheless, we show that efficient algorithms exist to compute both
exact and approximate solutions for the problem. In particular, we develop an exact solution of pseudo-polynomial
complexity, as well as an ǫ-optimal approximation of polynomial complexity. Simulation results are also provided
to show the utility of our algorithms and quantify their energy savings compared to a combination of (standard)
security-agnostic minimum energy routing and physical layer security. In the simulated scenarios, we observe that, by
jointly optimizing link selection at the network layer and cooperative jamming at the physical layer, our algorithms
reduce the network energy consumption by half.