Whether you're a designer, an engineer, a product owner, or just a user, understanding the tools you build and use requires a whole-systems understanding of both how they work and how they fail. We often think of security as being something obscure and mostly important for the low-level parts of software systems, but the part of security that matters to most people is actually about human outcomes. Likewise, we often think of participation as just some of ineffable thing that people do, most closely approached by coarse measures like "engagement". When we get beyond this, we find that the same tools that help us understand how participation works in systems can teach us about what security means in those systems. The tools for thinking systemically and holistically about both participation and security are still in their infancy, but this talk will look at some starting points.