When you design identity and access management (IAM) systems, consider psychology and sociology in addition to computer security. The goal of this talk is to describe the human-computer interaction problems presented by IAM and three real-world patterns with open-source implementations for managing AWS IAM in an organization. The cloud is a powerful force that changes the way we defend against adversarial software. More of us are shipping more code, more often. We use IAM systems to communicate our expectations about our code’s behavior to the machines running it. Vague specifications and impedance mismatches between human biases and machine logic make this communication channel lossy. Without careful consideration, our software can be exploited to turn against us.