/ Arup Guha
/ 11/7/06
/
/ Solution for CIS 3362 DES Project
/
/
/
/
/
There are many weaknesses in this solution due to my laziness!
All of the constants in the algorithm should be stored in final
static variables, but I just wanted to read in the informa
CIS 3362 Reference Sheet Letter Number Letter Number Value Inverse Mod 26 A 0 N 13 1 1 B 1 O 14 C 2 P 15 3 9 D 3 Q 16 E 4 R 17 5 21 F 5 S 18 G 6 T 19 7 15 H 7 U 20 11 19 I 8 V 21 J 9 W 22 17 23 K 10 X 23 L 11 Y 24 25 25 M 12 Z 25
Frequency Information of
Introduction to Cryptography and InformationSecurity
CIS 3362

Fall 2012
CIS 3362 Test #2: Modern Symmetric Encryption Schemes (DES, AES) Solutions
Date: 10/10/2012
1) (16 pts) Consider a cipher that uses a 16 bit key and 16 bit blocks. Let A and B both be
permutations matrices used in the cipher, assuming that A and B are exp
Introduction to Cryptography and InformationSecurity
CIS 3362

Fall 2012
Fall 2012 CIS 3362 Homework #1 Solutions
1) (On Quiz) First we switch x and y in the given encryption function:
x = (23y + 42) mod 62
Now, lets solve for y:
23y = (x 42) mod 62
We must now find 231 mod 62:
62 = 2 x 23 + 16
23 = 1 x 16 + 7
16 = 2 x 7 + 2
Introduction to Cryptography and InformationSecurity
CIS 3362

Fall 2012
Fall 2012 CIS 3362 Homework #2 Solutions
1) Using the Index of Coincidence test, 9 comes up as the most likely length of the keyword. In
playing with the letter frequencies, the keyword is revealed to be: JOHNCHITT, the president of
UCF. Here is the corre
Introduction to Cryptography and Information Security
CIS 3362

Fall 2013
Exam #3 Review Question Solutions
1) What is the prime factorization of 175?
175 = 52 x 7
2) Prove that 2 is a generator mod 13.
21 2 mod 13
22 4 mod 13
23 8 mod 13
24 3 mod 13
25 6 mod 13
26 12 mod 13
27 11 mod 13
28 9 mod 13
29 5 mod 13
210 10 mod 13
21
CIS 3362 Test #2: Modern Symmetric Encryption Schemes (DES, AES) Solutions Date: 10/10/2012
1) (16 pts) Consider a cipher that uses a 16 bit key and 16 bit blocks. Let A and B both be permutations matrices used in the cipher, assuming that A and B are exp
/ Arup Guha
/ 11/7/06
/ Solution for CIS 3362 DES Project
/
/
/
/
There are many weaknesses in this solution due to my laziness!
All of the constants in the algorithm should be stored in final
static variables, but I just wanted to read in the information
DiffieHellman Key Exchange Motivation for Key Exchange Algorithm The fastest encryption schemes are symmetric encryption schemes. In order to use these, the two communicators (Alice & Bob) would have to meet in a secure location. BUT, this sort of defeat
CIS 3362 Exam #2 Review Questions
1) Break the following permutation cipher:
Mmeeuabxnolrbiwltweoekbpoon
2) What is the result of encrypting
goodlucktotheprogrammingteam
using a column permutation cipher with the keyword homes and the padding character z?
CIS 3362 Exam #2 Review Solutions
1) The key length is 9. (The message is of length 27 and 3 doesn't work, even when
trying all 6 permutations.) The encryption key is 3, 8, 6, 1, 9, 5, 2, 7, 4.
Plaintext: examnumbertwowill beopenbook
2) Here is the grid:
CIS 3362 Test #2: Modern Symmetric Encryption Schemes (DES, AES) Solutions
Date: 10/10/2012
1) (16 pts) Consider a cipher that uses a 16 bit key and 16 bit blocks. Let A and B both be
permutations matrices used in the cipher, assuming that A and B are exp
Introduction to Cryptography and Information Security
CIS 3362

Fall 2013
CIS 3362 Test #2: Modern Symmetric Encryption Schemes (DES, AES) Solution
Date: 10/4/2013
1) (20 pts) Consider a simple cryptosystem with a 16 bit block and 16 bit key as follows:
Step 1: Compute C0 = A(P), where A is the permutation matrix shown below.
S
Introduction to Cryptography and Information Security
CIS 3362

Fall 2013
CIS 3362 Test #2: Modern Symmetric Encryption Schemes (DES, AES) Solution
Date: 10/10/2011
1) (16 pts) Consider a cipher that uses a 16 bit key and 16 bit blocks. Let A and B both be
permutations matrices used in the cipher, assuming that A and B are expr
Introduction to Cryptography and Information Security
CIS 3362

Spring 2016
5) Every week I listen to a podcast called the co optional podcast. They are a podcast who broadcast
live on the website twitch.tv. Sometimes on the podcast, one of the hosts will mention another
website and the viewers will immediately search for it caus
Introduction to Cryptography and Information Security
CIS 3362

Spring 2016
7) COMPUTERSECURITY
BLUEBLUEBLUEBLUE
DZGTVEYVTPWYSTNC
8) O R L A N
DBCEF
G H I/J K M
PQSTU
VWXYZ
IT SC OX OL GO IN GT OS CH OX OL
KS XI LV RA PD ML IP LP BI LV RA
9) (800)(400000) = 3.2 x 108 Keys/sec
(3.2 x 108)(86400) = 2.7648 x 1013 keys/day
(251) / (2