Multi-Tenant Secure Kubernetes Deployment for Trading Platforms

Design a Kubernetes multi-tenant architecture for a high-frequency trading platform that guarantees complete network isolation between different trading teams. Create a comprehensive namespace strategy with RBAC policies that implement strict role-based access controls, including granular Pod Security Policies. Include a detailed network policy configuration that prevents cross-namespace communication while allowing controlled, auditable inter-service interactions. Demonstrate how you'll implement encryption at rest and in transit using Kubernetes secrets management and integrate with a financial-grade key management system.