I wrote knockknock because I couldn't find a non-insane port knocker that employed the use of cryptography over a simple knock sequence: http://www.thoughtcrime

I wrote knockknock because I couldn't find a non-insane port knocker that employed the use of cryptography over a simple knock sequence: http://www.thoughtcrime.org/software/knockknock/ http://www.thoughtcrime.org/software/knockknock/