A logic circuit for managing reception of secure data packets in an industrial controller snoops data being transferred by a Media Access Controller (MAC) between a network port and a shared memory location within the industrial controller. The logic circuit is configured to perform authentication and/or decryption on the data packet as the data packet is being transferred between the port and the shared memory location. The logic circuit performs authentication as the data is being transferred and completes authentication shortly after the MAC has completed transferring the data to the shared memory. The logic circuit coordinates operation with the MAC and signals a Software Packet Processing (SPP) module when authentication is complete. The logic circuit is further configured to decrypt the data packet, if necessary, and to similarly coordinate operation with the MAC and delay signaling the SPP module that data is ready until decryption is complete.