1. Cryptography

2. What is cryptography?
The process of writing or solving secret messages or codes.

4. dadada

5. An algorithm used to encrypt a message.
What is a cipher?
An algorithm used to encrypt a message.

6. Substitution Cipher One alphabet: Monoalphabetic substitution
Initial alphabet: ABCDEFGHIJKLMNOPQRSTUVWXYZ
Substitution cipher: DEFGHIJKLMNOPQRSTUVWXYZABC
Multiple alphabets: Polyalphabetic substitution
Initial alphabet: ABCDEFGHIJKLMNOPQRSTUVWXYZ
Substitution cipher 1: DEFGHIJKLMNOPQRSTUVWXYZABC
Substitution cipher 2: GHIJKLMNOPQRSTUVWXYZABCDEF
Substitution cipher 3: JKLMNOPQRSTUVWXYZABCDEFGHI
Substitution cipher 4: MNOPQRSTUVWXYZABCDEFGHIJKL
“MOM” becomes… “PRP”
“JOHN” becomes… “MUQZ”

7. Your turn…
Initial alphabet: ABCDEFGHIJKLMNOPQRSTUVWXYZ Substitution cipher 1: DEFGHIJKLMNOPQRSTUVWXYZABC Substitution cipher 2: GHIJKLMNOPQRSTUVWXYZABCDEF Substitution cipher 3: JKLMNOPQRSTUVWXYZABCDEFGHI Substitution cipher 4: MNOPQRSTUVWXYZABCDEFGHIJKL Ciphertext: ERDQ Plaintext: ???
Plaintext: BLUE
BLUE

8. Vernam Cipher
Plaintext: S P A R E N O O N E Plaintext value: One-time pad text: E H T Z L A C D G J One-time pad value: Sum of plaintext & pad: After modulo subtraction: 18 Ciphertext: X X U R Q O R S U O

9. Your turn… Plaintext: M E E T A T S T A R B U C K S
Pad text: I M W L V Q N E Y B P A F R M
Sum:
Modulo subtraction:
Ciphertext: ???
Ciphertext: VRBFWKGYZTRVICF
VRBFWKGYZTRVICF

10. Book Cipher 134, 8, 9; 23, 13, 6; 67, 7, 7; One word End of word
Word Number (in line)
Page Number
Line Number (on page)

11. “Plague affected Michigan”
Your turn…
166, 18, 6; 105, 28, 3; 61, 25, 5;
Plaintext: Plague affected Michigan
“Plague affected Michigan”

12. Encryption in everyday life
From your survey results, 11% of your class uses Encryption to secure their files 89% of your class uses secure Wi-Fi 67% of your class has online accounts … but only 20% have different passwords (80% have 5 or less) 89% of your class is connects to Bluetooth

13. Relation to Business Human Resources Marketing Operations
Finance/Accounting

14. Questions?
Sources:
Principles of Information Security, 5th Edition; Michael E. Whitman; Herbert J. Mattord