The Baconian Cypher

After reading over some of my old blog posts, I felt inspired to write another cryptography post. I really enjoy the topic and I like keeping a record of codes I study with these little monographs.

In this post I will discuss the Baconian Cypher. I first heard about this cypher from an old Sherlock Holmes radio program by the same name. It was created by renaissance man, Sir Francis Bacon, hence it's name. Without further ado, I present to you the Baconian Cypher.

A   00000   G     00110   N    01100   T     10010
B   00001   H     00111   O    01101   U/V   10011
C   00010   I/J   01000   P    01110   W     10010
D   00011   K     01001   Q    01111   X     10101
E   00100   L     01010   R    10000   Y     10110
F   00101   M     01011   S    10001   Z     10111

Traditionally As and Bs are used for illustrating the cypher, but like Morse Code, one only needs to use a two choice operator, i.e. on/off, true/false, dot/dash, or as in my case, 1s and 0s, like binary. It is, in fact similar to binary, but I won't go into that right now. Because of this two choice operation, the cypher can be used in a wide range of uses. I'll be explaining the most common use of this cypher, which is hiding a message in non-related text.

Say I want to encode the word "now". I would take the pattern from N, O, and W, and it would look like this: 011000110110010.

Now take a text 15 characters long (because "now" has 3 letters and each letter of the encoded text needs 5 characters in the text, 3*5=15). I will use "A Study in Purple." including the period as an additional character.

I will leave the 0 letters as they are and then put the 1 letters in bold, but one could italicize them, underline them, or use a different font, so long as a distinction between 0s and 1s can be made. It looks like this:

"A Study in Purple."

This could can be used with a book: all one would have to do is underline letters (or even whole sentences) to form "1"s.

Polybius Checkerboard Cypher

The Polybius Checkerboard (otherwise known as the Greek square) was named for the ancient Greek historian to whom its invention is due. The original set up is quite simple, but variations on it can be quite hard to break. One variation was used by a spy in the American Civil War, and it was never broken by the enemy.

Below is the basic version.

	1	2	3	4	5
1	a	b	c	d	e
2	f	g	h	ij	k
3	l	m	n	o	p
4	q	r	s	t	u
5	v	w	x	y	z

Yes, I did write out all of the html for that table, feel free to use it if you wish.

To use this cypher one substitutes the row number and the column number, for the letter. For example:

"A Study in Purple" becomes

11 43 44 45 14 54 24 33 35 45 42 35 31 15 or

1143444514542433354542353115 or

11434 44514 54243 33545 42353 11500 or even

1 1434 445 14 5424 333 5454 23531 15

So obviously one of the variations of the Polybius Checkerboard is spacing. Other variations include: scrambling the letters and/or numbers of the square and using different alphabets (this is called a "Greek Square" because it was originally used the Greek alphabet). I thought it would be neat for short messages to also be encoded mathematically, for example:

Take the square root of 1,143,444,514,542,433,354,542,353,115 then divide it by 999,999,999, then subtract 330,000 from it, and the number becomes 8,148.564434 (much more portable in my opinion). It would be impossible to crack without knowing what steps to take to reverse the function. One could even take 8,148.564434, divide it by as many people as one wants to give the code to, and have them only be able to come up with the right message when all of the individuals add their values. The variation possibilities are endless! Here is an exercise in breaking a Polybius Checkerboard, use the square above, I only used a spacing variation.

...213442-442315-243454-3421-54235123-2443-54344542-4344421533224423.

Fersen Cypher

I know that there is much more to the Fresen-Anoinette codes and it is an interesting study, but for lack of a better name for this perticular cypher I have just decided to call it "Fersen".

This is a substitution code, but I find the method of substitition very interesting. Though it is a simple code, it can be used with other forms of cyphers to create a stronger code. But without further ado here is the Fersen Cypher.

A-B
C-D
E-F
G-H
I-J
K-L
M-N
O-P
Q-R
S-T
U-V
W-X
Y-Z

For those who are familier with this cypher: (For those who aren't you can ignore this)
I know I split 'I' and 'J', but it works out neater this way.

This is how it works:

Take my blog name:

A Study in Purple

A becomes B, S becomes T, T becomes S, U becomes V, etc. So incrypted "A Study in Purple" becomes:

B TSVDZ JM OVQOKF.

Simple, non? But then take the encoded name and put it into a geometrical cypher:

B
TS
VDZ
JMOQ
-OKF-

Now we have the incryption: BSZQ TDOF VMK JO. Even if the Fersen code is simple and easy to break, adding a geometric scrambling with make this code multiple times stronger. It makes the geometric shape almost impossible to find because no matter how many shapes one tries, not a single one will produce the message.

Geometric Cyphers

I will be putting up some of my old posts, like this one.

I have been enjoying Geometry the last few weeks. I love it! Who wouldn't enjoy practical logic puzzles that involve mathematics? I also love cryptology. One of the many ways of encrpting information is by using a geometric shape, such a triangle, rombus, rectangle, or square, to scramble the letters of a message in a fashion that is easily reversed... if you know or can find the correct shape.

For example, take the message "Come at once." in a triangle:

C
AO
NTM
ECOE

The message can now be read as: CAONTMECOE, with spacing as disired, sets of 5 are traditional, but various sets of random lengths may cause a code breaker to try breaking it as a substitution code. It can also be read as: ENACCTOME, ECOENTMAOC, or CANEOTCMOE.

Below, I have a sample that you can try to decrypt, it is a very simple one, I used one of the shapes mentioned above, and the text, once properly arranged, is easily read left to right. The dash in the code is an empty square in the shape. Graph paper is very useful (if you do not use a computer).

TTTH HHHI EEES HGFH ELIA AORN VRMD EYAY NOMW
SFEO DGNR EOTK CDSP LAHS ANOA RDWL E-SM

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