The pigpen cipher is a geometric simple substitution cipher, which exchanges
letters for symbols which are fragments of a grid. The example key shows one way
the letters can be assigned to the grid. Security
The use of symbols instead of letters is no impediment to cryptanalysis, and this
system is identical to that of other simple monoalphabetic substitution
schemes. Due to the simplicity of the cipher, it is often included in
children's books on ciphers and secret writing.
History The exact origin of the cipher is
uncertain, but records of this system have been found which go back to at
least the 18th century. Variations of this cipher were used by both the
Rosicrucian brotherhood and the Freemasons, though the latter used it so
often that the system is frequently called the Freemason's cipher. They
began using it in the early 18th century to keep their records of history and
rites private, and for correspondence between lodge leaders. Tombstones of
Freemasons can also be found which use the system as part of the engravings.
One of the earliest stones in Trinity Church Cemetery in New York City, which
opened in 1697, contains a cipher of this type which deciphers to "Remember
death". George Washington's army had documentation about the system, with a
much more randomized form of the alphabet. And during the American Civil
War, the system was used by Union prisoners in Confederate prisons.
Variants The core elements of this system are the
grid and dots. Some systems use the X's, but even these can be rearranged. One
commonly used method orders the symbols as shown in the above image: grid, grid,
X, X. Another commonly used system orders the symbols as grid, X, grid, X.
Another is grid, grid, grid, with each cell having a letter of the alphabet,
and the last one having an "&" character. Letters from the first grid
have no dot, letters from the second each have one dot, and letters from the
third each have two dots. Another variation of this last one is called the
Newark Cipher, which instead of dots uses one to three short lines which may
be projecting in any length or orientation. This gives the illusion of
a larger number of different characters than actually exist.
Another system, used by the Rosicrucians, used a single grid of nine
cells, and 1 to 3 dots in each cell or "pen". So ABC would be in the top left
pen, followed by DEF and GHI on the first line, then groups of JKL MNO PQR
on the second, and STU VWX YZ on the third. When enciphered, the location of
the dot in each symbol, would indicate which letter in that pen was
represented. More difficult systems use a non-standard form of the alphabet,
such as writing it backwards in the grid, up and down in the columns, or a
completely randomized set of letters. The Templar cipher is a method claimed
to have been used by the Knights Templar. It uses a variant of a Maltese
Cross. Example
Using the Pigpen cipher key above, the message "X MARKS THE SPOT" is rendered
in ciphertext as: In popular culture
The Pigpen cipher has been used in several works of popular culture
including Dan Brown's 2009 novel The Lost Symbol, both in the book itself,
and also to provide a puzzle in the artwork of the U.S. version of the
bookjacket. The Trap, a 2009 nominee for Lancashire Children's Book of the Year,
uses a variation of the Pigpen cipher. Author Clifford B. Hicks included the
cipher in his 1963 children's book Alvin's Secret Code, with title
character Alvin Fernald explaining its use by Civil War soldiers.
Used in the book The Voyage of the Mimi. The cover of the Outfield's 1989 album,
Voices of Babylon, is written in a pigpen cipher similar to the version
shown to the right, as are the song titles in the album's liner notes.
The 39 clues series of popular children's books uses pigpen cipher in
many of its puzzles in books and its gaming website.
In the game Assassin's Creed II, a variant of Pigpen is used to provide
additional information about the story, in addition to Morse Code and binary
code. In the novel Time Riders: The Doomsday
Code, it is used to encrypt a message to the present day from the past.
The BBC series Sherlock has created a website to correlate with the events in
the series - The Science of Deduction. Under the "Hidden Messages" tab,
"Sherlock" lists three coded messages he received from a stalker, and the third
is in pigpen cipher. The message says "Sherlock I have found you".
In Club Penguin, a children's MMO, a modified pigpen cipher is used in the
"Secret Agent" aspect of the game. In the beginning of Linkin Park's "In
the End" music video, the doorway that Chester emerges from is inscribed in
Pigpen symbols In the Call of Duty: Black Ops II
Zombies map 'Buried', the Pigpen cipher forms part of the quest for players to
complete an 'Easter Egg' achievement. Players are required to decipher a code
in order to proceed on with the quest. The code uses a cipher based on the
letters of the alphabet being grouped into three letters with the
corresponding letter being annotated by a line inside the cipher.
Notes References
Barker, Wayne G., ed.. The History of Codes and Ciphers in the United States
Prior to World War I. Aegean Park Press. ISBN 0-89412-026-3.
Gardner, Martin. Codes, ciphers and secret writing. ISBN 0-486-24761-9.
Kahn, David. The Codebreakers. The Story of Secret Writing. Macmillan.
Kahn, David. The Codebreakers. The Story of Secret Writing. Scribner. ISBN
0-684-83130-9. Newton, David E.. "Freemason's Cipher".
Encyclopedia of Cryptology. ISBN 0-87436-772-7.
Pratt, Fletcher. Secret and Urgent: The story of codes and ciphers. Aegean Park
Press. ISBN 0-89412-261-4. Shulman, David; Weintraub, Joseph. A
glossary of cryptography. Crypto Press. p. 44.
Wrixon, Fred B.. Codes, Ciphers, and other Cryptic & Clandestine
Communication. Black Dog & Leventhal Publishers, Inc. ISBN 1-57912-040-7.
External links The Elian Script is a similar grid-based
cipher, used as art. Online Pigpen cipher tool for
enciphering small messages. Cipher Code True Type Font
Cryptii converts text in pigpen cipher and more.