Assess learners' ability to evaluate trade-offs among Proof of Work (PoW), Proof of Stake (PoS), and Practical Byzantine Fault Tolerance (PBFT) across security (attack surfaces, fault tolerance, finality), performance (latency, throughput), and scalability (network size, sharding). Require comparison of suitability in permissioned versus permissionless deployments, discussion of economic incentives and governance implications, and justification of consensus selection for specific use cases with proposed mitigations for identified risks. Scope: advanced-level conceptual and applied analysis, no implementation required.