Representative embodiments are disclosed for providing network and system security. A representative apparatus includes an input-output connector coupleable to a data network; a network interface circuit having a communication port; a nonvolatile memory storing a configuration bit image; and a field programmable gate array (“FPGA”) coupled to the network interface circuit through the communication port, the FPGA configurable to appear solely as a communication device to the first network interface circuit, and to bidirectionally monitor all data packets transferred between the input-output connector and the first network interface circuit and any coupled host computing system. In another embodiment, the FPGA is further configurable for only a partial implementation of a communication protocol, such as a PCIe data link and/or physical layers. The FPGA may also monitor host memory and provide encryption and decryption functionality. The FPGA is not addressable within the computing system and therefore is largely undetectable by malware.