Double Adianoeta is a protocol that provides four layers of meaning from a single message that is called the CarrierStory. Text and keys can be distributed in one steganographic message. The layers are numbered 1 through 4. In a CarrierStory (1) that only displays a foreign text, the embedded layers are called the WordMirror (2), Texstego (3), and SecretFont (4). The first layer will baffle most people and the last three layers deliver three different messages.
The CarrierStory looks like an essay written in a foreign alphabet. The WordMirror layer produces the CarrierStory from English sentences. A trained person can read the sentences directly from the foreign glyphs to get a first secret message. The Texstego layer uses counts of characters in pairs of sentences in the CarrierStory to deliver two digit numbers that map to Latin characters. That provides a second secret message. The SecretFont layer has a TrueType Font file that is shared by only the sender and the intended recipient, and which is not possessed by other people. That SecretFont is used to replace the foreign glyph fonts with Latin glyphs that use the Unicode code points for the foreign glyphs. When the SecretFont is installed, the CarrierStory displays English words using standard Latin characters so that a third secret message is delivered to the intended recipient, but not to people who do not have the SecretFont file.
The Double Adianoeta protocol is intended to have three advantages over other algorithms and protocols. The first advantage is that the layers fool investigators with plausible messages that prompt them to abandon further analysis when one plausible explanation is understood. The second advantage is that machines cannot easily interpret the meanings in the layers, but humans can interpret them after some training on public websites. The third advantage is that each layer uses weak cryptography so that it might be legal to post related software files on the internet without violating laws.
Programs and Files from Website Links Supporting the Four Layers
Layer 1 : CarrierStory in Cuneiform, Greek, and Cyrillic Unicode
Layer 2 : WordMirror in Perl and C#
Layer 3 : Texstego Perl Programs
Layer 4 : SecretFont Using .ttf TrueType Fonts
A single program will be written in the C++ language to produce files that a sender needs and to allow a recipient to extract meaningful messages. The unified program provides a form that a sender can fill out to create the CarrierStory Unicode file and the SecretFont.ttf file. The inputs will be a text file story, a texstego message, and a secretfont message. The recipient uses the unified program to enter the texstego key and to show the path to the secretfont file. If a default texstego key is not being used, the recipient needs to visually read the carrier story to get the texstego key. The human recipient has advantages over machines when interpreting three messages to calculate the key. The human intelligence understands instructions given from the WordMirror, the Texstego, and SecretFont messages.