VHDL and Verilog HDL are standards languages for hardware description. Sometimes is necessary to share the source HDL file but maintaining a little level of control and protection of the intellectual property. This tool generate obfuscated code that is almost unreadable to humans, but is still readable to compilers and simulators.
This tool use GHDL (https://sourceforge.net/projects/ghdl-updates/), HDLObf (https://sourceforge.net/projects/hdlobf/), Icarus Verilog...