Applied Cryptography Assignment 2022

Running head: APPLIED CRYPTOGRAPHY
APPLIED CRYPTOGRAPHY
Name of the Student
Name of the University
Author Note

APPLIED CRYPTOGRAPHY 1
Caesar Cipher:
The Caesar cipher technique is one of the simplest and earliest methods for encryption
and decryption. This is actually a kind of substitution cipher. Each of the letters of a provided
text is replaced by another letter with some fix number of positions. As example it can be said
that with the shift of 2, B will be replaced by D, and E will become G and So on. This
encryption can be presented utilizing the modular arithmetic by transforming the letters in to
number firstly. According to that A = 0, B = 1..... Z = 25.
1. Create a frequency analysis chart for your ciphertext (include a screenshot of this chart in
your report).
Cipher text:
fqjc j cdaw cqnv kjwmjpnb mrm pren vn cx kn bdan bqn ydc xw bxvn vxan lxju dwoxumnm
cqn luxcqnbqxabn
0 A
1 B
2 C
3 D
4 E
5 F
6 G
7 H
8 I
9 J
10 K
11 L
12 M
13 N
14 O
15 P
16 Q
17 R
18 S
19 T
20 U

APPLIED CRYPTOGRAPHY 2
21 V
22 W
23 X
24 Y
25 Z
2. Refer to your frequency chart and identify the ciphertext character that most likely
represents the plaintext character ‘e’. Justify your answer.
Frequency analysis:
The letter that is having the most percentage is N, 16.05%. As most of the letters in the
English language is ‘E’, We are considering the letter ‘N’ from cipher text.
3. Determine the key used with the Caesar cipher. Explain how you obtained this key.
Decryption procedure:
The CrypTool 2 has been used for obtaining the key.
It is found in Templates -> Cryptography -> Classical to find the Caesar Cipher template.
Number Value = 25
grkd k debx drow lkxnkqoc nsn qsfo wo dy lo cebo cro zed yx cywo wybo mykv expyvnon
dro mvydrocrybco
Number Value = 24

APPLIED CRYPTOGRAPHY 3
hsle l efcy espx mlyolrpd oto rtgp xp ez mp dfcp dsp afe zy dzxp xzcp nzlw fyqzwopo esp
nwzespdszcdp
Number shift = 23
itmf m fgdz ftqy nmzpmsqe pup suhq yq fa nq egdq etq bgf az eayq yadq oamx gzraxpqp ftq
oxaftqetadeq
4. Provide the plaintext corresponding to the ciphertext you were given.
Starcenter > templates > Cipher analysis
Plain text:
Number value: 9
what a turn them bandages did give me to be sure she put on some more coal unfolded the
clotheshorse
Row/column Transposition Cipher:
The transposition cipher is basically a simple data encryption technique in that the
characters of plaintext are shifted in a regular pattern for getting ciphertext.
1. Create a frequency analysis chart for your ciphertext.