Various example embodiments for supporting zero-trust policy enforcement in a communication system are presented herein. Various example embodiments for supporting zero-trust policy enforcement in a communication system may be configured to support zero-trust policy enforcement, including zero-trust authentication, for Remote Direct Memory Access (RDMA) communications. Various example embodiments for supporting zero-trust policy enforcement for RDMA communications may be configured to support transparent zero-trust policy enforcement for RDMA communications by leveraging programmable Smart Network Interface Cards (SmartNICs). Various example embodiments for supporting zero-trust policy enforcement for RDMA communications based on leveraging of programmable SmartNICs may be configured to support zero-trust policy enforcement for RDMA communications by applying zero-trust policies on a connection-by-connection basis within SmartNICs for RDMA connections between RDMA applications hosted on end hosts served by the SmartNICs.