http://swonderstzr43aczpcwdoyc25vwxngyromja7pyb5sf26ap3v535sxqd.onion/resources/an-introduction-to-steganography
First Recorded use of Steganography The first known use of steganography is traced back to 440BC in Greece with two recorded uses which involved: A
Greek ruler shaving the head of his most trusted servant and marking
the message onto his scalp and sending him to the destination when the
hair was regrown concealing the message.