1. Discuss the difference between Authentication and Authorization.
2. What is the plain text of a substitution cipher?
(a) Using a Caesar Cipher with a key of 3 (shift by 3), what is the plaintext if the ciphertext is FUB- SWRJUDSKB FDQ EH IXQ? Work by hand and show all work. Hint: If your solution is nonsense, it is probably incorrect.
(b) Using any means available (Google is your friend) on a Substitution Cipher with an unknown key of a random alphabet:
i. Find the plaintext if the cipher text is: EXUYGJMJAUVZV ZV RCGWM BZCCZENAG
ii. Explain with enough detail to duplicate your method how you solved this.
iii. Find the key and explain how you did it (Hint: it will be a mapping of each character used in the cipher text to a corresponding character in the plain text. i.e. A = M, B = Q, etc.).
ciphertext a b c e g j m n r u v w x y z
plaintext l d f c t a n u o y s e r p i
3. Transposition ciphers
(a) Solve the following Grille cipher using the included cut out. Briefly describe your method of breaking the cipher.
(a) Original grid
(b) YOUB
(c) ROKE
(d) THEC
(e) ODES
(b) Solve the following Double Transposition cipher. Briefly describe your method of breaking the cipher.
(a) Original Order
(b) Col. 2 ⇔ Col. 4 (c) Reversed rows
(d) Final position
4. What is the one-time pad for encryption?
(a) What is the one time pad used if the plain text is “thrill”?
Plaintext
T
H
R
I
L
L
Encoded Plaintext
111
001
101
010
100
100
Ciphertext
K
I
T
L
K
E
Encoded Ciphertext
011
010
111
100
011
000
(b) Whats the key if the plain text was “tiller”?
Plaintext
T
I
L
L
E
R
Encoded Plaintext
111
010
100
100
000
101
Ciphertext
K
I
T
L
K
E
Encoded Ciphertext
011
010
111
100
011
000
5. Solve the following null cipher (you do not need to show work or describe how you solved this, but understanding how the answer is derived is still important).
6. BONUS
Using any means available, find the plaintext for the following ciphertext and explain briefly but with enough detail to duplicate your method how you solved this:
Again, using https://quipqiup.com, this is decrypted rather quickly. On this website, it is as simple as pasting in raw ciphertext, clicking “Solve” and letting the website do it’s job. It’s remarkably quick and accurate.
