We describe IODINE, a tool to automatically extract likely design properties using dynamic analysis. A practical bottleneck in the formal verification of hardware designs is the need to manually specify design-specific properties. IODINE presents a way to automatically extract properties such as state machine protocols, request-acknowledge pairs, and mutual exclusion between signals from design simulations. We show that dynamic invariant detection for hardware designs can infer relevant and accurate properties. Categories and Subject Descriptors: B.5.2 Hardware Register-Transfer-Level Implementation Verification F.3.1 Theory of Computation Logics and Meanings of Programs Invariants General Terms: Verification, Algorithms