# HW1-CIS 4361

### CIS 4361 Spring 2012 Homework I (due Friday Feb 3, starting class)

1) For substitution cipher, use the keyword MESSAGE to encrypt the message “Florida is the sunshine state”. 2) Construct the Playfair matrix using the keyword GRADUATION and encrypt message “This class is my favorite class”. 3) Encrypt the hexadecimal message

B57A

using the Rail Fence cipher for binary numbers with 3 Rails. [Give answer in hexadecimal encrypted message]. 4) Decrypt the hexadecimal encrypted message

ABCD

created by the Rail Fence cipher for binary numbers with 3 Rails. [Give answer in hexadecimal message]. 5)

[10]

Permute the input 0101 1101 1011 1000, if a permutation is defined as follows: 1 2 3 4 5 6 7 8 11 13 7 9 3 5 15 1 9 13 10 14 11 15 12 16 10 12 6 8 2 4 14 16 6) Given the following permutation, 0 13 1 14 2 15 3 16 4 17 5 18 6 19 ↓ 7 20 8 21 9 22 10 23 11 24 12 25 18 5 19 6 20 7 21 8 22 9 23 10 24 11 25 12 0 13 1 14 2 15 3 16 4 17 a.

Find the Caesar cipher equation and the Caesar cipher alphabet that has been used. b.

Find the encrypted message for “Examination one is coming soon”. 7)

[

Given the Caesar cipher equation

c

= E(

p

) = (

p

+

4

) mod (26), find the permuted box for the following initial box: 0 13 1 14 2 15 3 16 4 17 5 18 6 19 7 20 8 21 9 22 10 23 11 24 12 25

8)

[

Given the following permutation, find the mono-alphabetic cipher that has been used? 0 13 1 14 2 15 3 16 4 17 5 18 6 19 7 20 8 21 9 22 10 23 11 24 12 25 2 4 0 13 3 5 1 14 1 7 2 15 6 25 3 16 0 24 4 17 22 23 5 18 ↓ 14 9 6 19 8 21 7 20 13 10 8 21 11 12 9 22 19 20 10 23 17 15 11 24 18 16 9) Given the plaintext alphabet: abcdefghijklmnopqrstuvwxyz and the mono-alphabetic cipher alphabet: bfergsutvqwpxdyozanckhjmil, find the permuted box for the following initial box: 12 25 A N B O C P D Q E R F S G T H U I V J W K X L Y M Z 10) Given the following permutation: 0 13 1 14 2 15 3 16 4 17 5 18 2 24 13 8 20 3 7 19 16 1 6 14 6 19 ↓ 22 11 7 20 0 5 8 21 9 17 9 22 12 25 10 23 15 21 11 24 23 10 12 25 4 18 A N B O C P D Q E R F S G T H U I V J W K X L Y M Z a.

b.

Find the mono-alphabetic cipher that has been used Using the mono-alphabetic cipher of part a, decrypt the message “xiipjywgibzcbhliodbjywnbqcp”