The trifid cipher is an extension of the bifid cipher, carrying it to another dimension. A trifid cipher uses three layers, each of three columns and three rows for a total of 3-cubed or 27 possible characters - the extra character frequently used for a full stop or a space (you will note that I have used it for '°' the degree character). Because I seek a way to incorporate numbers into the cipher, I have used ten of the alphabetic characters to represent a numeral as well as themselves. In many cases, the numeral/alpha choice is obvious: I=1 and O=0' for instance. Some numerals do not have obvious matches, but if their identities are agreed upon beforehand, the fact that a character should be interpreted as a number can be gathered from context. In this example, I have substituted I=1, Z=2, E=3, A=4, S=5, P=6, L=7, B=8, Y=9 & O=0 (E is similar to a reflection of 3, A looks a little like 4, P could rotate to be a mirror image of 6, L can rotate to be 7, B resembles 8 and Y looks a little like 9).
Keywords are used at the upper left corner of the top layer and carried out as in a bifid arrangement. The keyword in the example is NATURE SANCTUARY which, when duplicates are dropped, becomes NATURESCY.
Encoding is done by entering the coordinates (layer, row, column) of each plaintext character vertically beneath it - note the use of letters to replace numbers::
The three rows of numbers are then read out appending each row after the one before it and ordered in triplets:
133 111 311 113 133 312 313 112 111 132 112 111 223 122 132 321 233 222 213 322
The triplets are re-encoded using the same cube - each triplet of coordinates resulting in a new character:
The resulting characters are written out. Groups of 5 are used to make it easier to handle.
(note that you may pad the plaintext with nulls to arrive at a number of characters evenly divisible by 5 if you so wish):
YNMTY OPANC ANIRC QLHFV
Sometimes a unique letter may be substituted for spaces in the plaintext before encoding. Because this message is short, there are many options, but even in a relatively long message, Q or X may remain unused and provide a good candidate. Inclusion of spaces is, of course, not essential, and in this message, spaces have been ignored.
To decode the message, the coordinates of each character are recorded in a line and broken into three equal parts:
13311131111313331231 ~ 31121111321121112231 ~ 22132321233222213322
The parts are written one below the other to reveal correct coordinates to read plaintext from the table.:
further discussion of trifid ciphers can be found at Wikipedia