Name:
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Please do not write in the spaces above.
Directions: This exam must be handed in at the beginning of the in-class exam on Friday. You may
not use anything but your class notes, class book, and the maplets (where I have given you
permission). You may not discuss the problems with anyone (other than me).
Important:
1. Make sure to break the plaintext into individual words.
2. Show work on the cryptanalysis problems.
Please attach this signed cover sheet to your work.
Good luck!
Please sign:
I,
content, with anyone.
, affirm that I have not discussed this exam, its questions, or its
Note: These are all to be done on maplets – do not attempt to do these by hand. Also, make sure you
break these up into words in English.
1. On Maplet (no work is needed here): Use the Enigma cipher with:
 4 rotors
 reflector B
 Rotors gamma, VI, VII, II
 Ring settings 11,23, 14, 2
 Window letters RELM
 Plugboard connections: AQ, WS, ZX, ED, CV, RF, VB, GT, YH, NJ
a. Decrypt the ciphertext:
PSUHO KBUXJ WLCXE QWVLR Y
b. Now reset the machine to the settings above. In this problem, we will also have a special message
key, as was done in reality (the special key will be typed in twice). Decrypt the ciphertext:
CJSPG DFOVZ MIGDK BAO
2. On Maplet (no work is needed here): Use the Navajo code to decrypt the ciphertext:
{ D-AH NE-AHS-JAH NA-AS-TSO-SI TLO-CHIN GAH DAH-NES-TSA TLO-CHIN GLOE-IH }
SEIS { TSE-NILL AH-JAD GLOE-IH WOL-LA-CHEE TSAH-AS-ZIH DIBEH } { CHUO GAH
DZEH DIBEH CHA } BILH { TSAH NE-AHS-JAH } { NA-AS-TSO-SI TKIN KLESH D-AH WOLLA-CHEE BA-AH-NE-DI-TININ DZEH DIBEH } { A-CHI TSAH } { YEH-HES D-AH } { TSAH-ASZIH AH-JAH THAN-ZIE }
3. On Maplet (no work is needed here): Use the modular reduction maplet to find the following:
a. -3439743876588664384638746 mod 4637362946266345
b. 7837493963782648762873628763 mod 235263752372575
4. On Maplet (no work is needed here): Use a simple phase shift cipher with b=22 to decrypt
EJKQN REHHW CABKH GOOWU CKZYN QIXHA OQLPD AKHZI KKJEJ PKOPW NO
5. On Maplet (Give all of your reasoning and steps here (there isn’t much):
Break the following phase shift cipher, using the maplet breaker and elementary statistical
analysis, i.e. by giving the breaker what plaintext letter corresponds to what ciphertext letter (tell
me what you told the maplet to use, and give all information that the maplet gave you).
ZKUFV JEFKU FNVCC KFUNV CCFEU IVRDJ REUWF IXVKK FCZMV IVDVD SVIKY RK
6. On Maplet (no work is needed here): Decipher the ciphertext PEJTD HSCJN RWJUD IPUCP
PXHRE YZQRS BHBEH BYJSQ JTUPW ZPWYH QROJS QJAPZ JWSPN QREFJ DH
which was encrypted using the affine cipher y=11x+17 mod 26.
7. This is to be done WITHOUT the maplets, showing all work:
We will be working in 33 here.
a. Make a list of the numbers in this set that have a multiplicative inverse in the set. Then fill in
the table below giving the inverses, and indicating any that do not have inverses by “NI” (for
“no inverse”)
a
a -1
0
1
2
3
4
5
6
7
a
a -1
8
9
10
11
12
13
14
15
a
a -1
16
17
18
19
20
21
22
23
a
a -1
24
25
26
27
28
29
30
31
Explain your process in a few sentences.
b. Then, using the table above, solve the following for x, showing all work:
7x - 23 = 200mod 33
c. Next, using the table above, solve the following for x, showing all work:
13x + 345 = ymod 33
d. Next, using the table above, solve the following for a and b, showing all work:
29a + b = 31mod 33
3a + b = 10 mod 33
e. Next, solve the following for x, showing all work: 3x + 3 = -81mod 33
f.
Last, solve the following for x, showing all work: 11x +19 = -301mod 33
32