Trifid Cipher
Encoding method:
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.
layer 1 |
layer 2 |
layer 3 |
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::
| C | O | M | E | A | T | O | N | C | E | T | O | R | O | O | M | 3 | 1 | 2 | 4 | ||||||
layer |
1 | 3 | 3 | 1 | 1 | 1 | 3 | 1 | 1 | 1 | 1 | 3 | 1 | 3 | 3 | 3 | 1 | 2 | 3 | 1 | |||||
row |
3 | 1 | 1 | 2 | 1 | 1 | 1 | 1 | 3 | 2 | 1 | 1 | 2 | 1 | 1 | 1 | 2 | 2 | 3 | 1 | |||||
column |
2 | 2 | 1 | 3 | 2 | 3 | 2 | 1 | 2 | 3 | 3 | 2 | 2 | 2 | 2 | 1 | 3 | 3 | 2 | 2 |
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:
| 1 | 1 | 3 | 1 | 1 | 3 | 3 | 1 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 3 | 2 | 2 | 2 | 3 |
| 3 | 1 | 1 | 1 | 3 | 1 | 1 | 1 | 1 | 3 | 1 | 1 | 2 | 2 | 3 | 2 | 3 | 2 | 1 | 2 |
| 3 | 1 | 1 | 3 | 3 | 2 | 3 | 2 | 1 | 2 | 2 | 1 | 3 | 2 | 2 | 1 | 3 | 2 | 3 | 2 |
| Y | N | M | T | Y | O | P | A | N | C | A | N | I | R | C | Q | L | H | F | V |
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.
Decoding:
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.:
| 1 | 3 | 3 | 1 | 1 | 1 | 3 | 1 | 1 | 1 | 1 | 3 | 1 | 3 | 3 | 3 | 1 | 2 | 3 | 1 |
| 3 | 1 | 1 | 2 | 1 | 1 | 1 | 1 | 3 | 2 | 1 | 1 | 2 | 1 | 1 | 1 | 2 | 2 | 3 | 1 |
| 2 | 2 | 1 | 3 | 2 | 3 | 2 | 1 | 2 | 3 | 3 | 2 | 2 | 2 | 2 | 1 | 3 | 3 | 2 | 2 |
| C | O | M | E | A | T | O | N | C | E | T | O | R | O | O | M | E | I | Z | A |
further discussion of trifid ciphers can be found at Wikipedia