Security issues and Internet of Things (IoT) become indispensable part in digital community as IoT develops with the pervasive introduction of additional “smart” sensors and devices over the last decades, and it necessitates the implementation of information security principle in digital community system. A three-level criticality model to determine the potential impact is proposed in digital community system when various devices lost in this paper. Combining the actual security requirement of digital community and characteristics of IoT, a hierarchical security architecture including defense-in-deep cybersecurity and distribute secure control is proposed. A high-assurance trust model, which assumes insider compromise, which exists in the digital community, is finally proposed according to the security issues analysis.