Matrix Ciphers - Introduction to Cryptography with Java Applets - page 158

EXERCISES

1.

Using the ordinary alphabet and a block size of 2, encipher and decipher the following
messages:
a.

GREY LADY DOWN

b.

WHERE EAGLES DARE

c.

TOKYO IN FLAMES
Pad with the letter X if necessary. Use the enciphering matrix

27
54

and shift vector

21
19

2. Repeat the previous exercise, but use a block size of 3 with the enciphering matrix

12 21 9
78 8
3 36

and the shift vector

19
5
6

3. Repeat the previous exercise, but use a block size of 5 with the enciphering matrix

20 15 3 1 5
4 3 643
3 8 13 10 8
12 15 4 3 2
56789

and the following shift vector

14
12
13
9
21

4. Suppose that you are a cryptanalyst trying to find the enciphering matrices used in the

previous exercises. Recover the enciphering matrix A and shift vector B from each of