In a data communication network, Network Interface Cards (NICs) receive user data and interrupt Central Processing Units (CPUs) that then transfer buffer descriptors for the user data to Data Memory Buffers (DMBs). The DMBs receive the buffer descriptors from the CPUs and transfer the buffer descriptors to the NICs. The NICs receive the buffer descriptors and responsively transfer the user data to the DMBs. The DMBs buffer the user data. A master NIC transfers a CPU hardware-trust validation challenge to a master CPU. The master CPU hashes the validation data with its physically-embedded, hardware-trust code to generate and transfer a CPU hardware-trust validation result. The master NIC processes the CPU hardware-trust validation result to verify hardware-trust of the master CPU.