Home medical devices enable individuals to monitor some of their own health information without the need for visits by nurses or trips to medical facilities. This enables more continuous information to be provided at lower cost and will lead to better healthcare outcomes. The technology depends on network communication of sensitive health data. Requirements for reliability and ease-of-use provide challenges for securing these communications. In this paper we look at protocols for the drop-box architecture, an approach to assisted living that relies on a partially-trusted Assisted Living Service Provider (ALSP). We sketch the requirements and architecture for assisted living based on this architecture and describe its communication protocols. In particular, we give a detailed description of its report and alarm transmission protocols and give an automated proof of correspondence theorems for them. Our formulation shows how to characterize the partial trust vested in the ALSP and use the existing tools to verify this partial trust.