Cryptology - Unofficial St. Mary's College of California Web Site

5.10. EXERCISES 85
13. Ciphers in which pairs of numbers replace each letter are called biliteral
or dinome ciphers. A simple way to construct such ciphers is to put
the letters of the alphabet into a rectangle and number the rows and the
columns. For example, if we use a five-by-five square, and squash i and j
together, we have
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
To encipher, replace the letter by its row–column number pair, that is,
read from the side first. So box becomes 12 34 53. Deciphering is just
translating back into letters.
Use the given square to encipher or decipher the following.
(a) rectangle.
(b) square.
(c) 54 66 53 56. (Hint: 41 was added to every number before transmission).
(d) 42 32 14 15 23 45 43. The alphabet was entered into the square
using the keyword DINOME.
(e) Perhaps the first ever use of a password was when Giovanni Argenti,
around 1589, used PIETRO and a rectangle with two rows and 10
columns (0 being the first). (The letters jkvwxy did not appear.) Using
this method, 17 16 13 13 11 27 13 16 and 24 16 13 13 12
15 gives Argenti’s middle name and his nephew’s name. What are
they
14. A larger bipartite cipher was used by Brig. General Leslie R. Groves
[Kahn, page 546]. It took the form
1 2 3 4 5 6 7 8 9 0
1 I P I O U O P N
2 W E U T E K L O
3 E U G N B T N S T
4 T A Z M D I O E
5 S V T J E Y H
6 N A O L N S U G O E
7 C B A F R S I R
8 I C W Y R U A M N
9 M V T H P D I X Q
0 L S R E T D E A H E