Secure one-way network gateway

Abstract

A secure one-way network gateway for transmitting data from a source network to a destination network is disclosed. An input circuit is for coupling to a source network and an output circuit is for coupling to an output network. A memory stores configuration data. Either a single field-programmable device or a pair of field-programmable devices coupled via a one-way link are inserted between the input circuit and the output circuit. The configuration data is loaded into the device(s) to program the device(s) to pass data from the input circuit to the output circuit, to optionally filter the data, and to prevent any data from passing from the output circuit to the input circuit. A processor is coupled to only the memory and a separate management interface. The processor receives updated configuration data via the management interface and replaces the configuration data in the memory with the updated configuration memory.

What is claimed is: 
     
         1 . A secure one-way network gateway for transmitting data from a source network to a destination network, comprising:
 an input circuit for coupling to the source network;   an output circuit for coupling to an output network;   a memory for storing configuration data;   a field-programmable device coupled between the input circuit and the output circuit, the field-programmable device configured to load the configuration data from the memory, the configuration data for programming the field-programmable device to pass data from the input circuit to the output circuit and to prevent any data from passing from the output circuit to the input circuit; and   a processor coupled to only the memory and a separate management interface, the processor configured to receive updated configuration data via the management interface and to replace the configuration data in the memory with the updated configuration memory.   
     
     
         2 . The secure one-way network gateway of  claim 1 , wherein the field-programmable device is a field programmable gate array. 
     
     
         3 . The secure one-way network gateway of  claim 1 , wherein the input circuit is a physical interface circuit. 
     
     
         4 . The secure one-way network gateway of  claim 1 , wherein the output circuit is a physical interface circuit. 
     
     
         5 . The secure one-way network gateway of  claim 1 , wherein the configuration data for the field-programmable device programs the field-programmable device to filter the data based on filter parameters before passing the filtered data to the output circuit. 
     
     
         6 . The secure one-way network gateway of  claim 5 , wherein the updated configuration data includes updated filter parameters. 
     
     
         7 . The secure one-way network gateway of  claim 1 , wherein the configuration data for the field-programmable device programs the field-programmable device to have a first portion and a second portion, the first portion coupled to the input circuit and the second portion coupled to the output circuit, the first portion capable of passing data to the second portion but not to receive data from the second portion, the second portion capable of receiving data from the second portion but not to pass data to the first portion. 
     
     
         8 . The secure one-way network gateway of  claim 1 , wherein the memory is within the field-programmable device. 
     
     
         9 . The secure one-way network gateway of  claim 1 , wherein the memory is within the processor. 
     
     
         10 . The secure one-way network gateway of  claim 1 , wherein the processor is an Advanced RISC (Reduced Instruction Set Computer) Machine (ARM) processor.