While not quite to the same level of obfuscation, your suggestion reminded me of this project: http://www.cipherdyne.org/fwknop/ http://www.cipherdyne.org/fwkno

While not quite to the same level of obfuscation, your suggestion reminded me of this project: http://www.cipherdyne.org/fwknop/ http://www.cipherdyne.org/fwknop/ Its essentially port knocking with a single encrypted packet. Haven't tried it (yet) myself but sounds interesting.