Breaking a Cypher Problem and Short Essay

Step 1. Read A Code Makers Guide,Step 2. Conduct a frequency analysis on the following text using the attached PDF. ( read the M6 and M62 PDF )A frequency count is tallying (counting) how many times each letter appears in a text.Text to analyzeThis worldwide reach benefited from close OSS contacts with British intelligence services. The British had much to teach their American pupils when COI opened its London office in November 1941. Both sides gained from the partnership. OSS needed information, training, and experience, all of which the British organizations could provide. The British good-naturedly envied the relative wealth of resources seemingly at the command of OSS and other American agencies and hoped to share in that bounty to expand their own operations against the Axis. Despite a mutual desire to cooperate, however, relative harmony between OSS and its British counterparts took time to achieve.You can print and use the attached sheet for your frequency count.Step 3. Decode the following message using the instructions in the Code Maker’s Guide and the frequency analysis you performed.Hints:1. Use your frequency analysis to see if you can guess any of the letters – e.g., “I” and “a” are the only one-letter words. Determine the five most and least used letters in the text. Determine common two-letter combinations and their frequencies (e.g., how often does “th” occur, compared to “t” followed by anything else?)2. Try using the secret password POLT in a cipher.Step 4. Write a copy of the decoded message in the submission text box below.Step 5. Write your submission on what you learned conducting this analysis. Make sure you define analysis. Answer the question what did you learn about intelligence analysis from breaking the cipher? Minimum 250 word submission.
message.jpg

a_code_makers_guide.pdf

freaquency_analysis_sheet_for_polt568.pdf

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Codemaker?s Guidelines
There are many different ways to create ciphers. Some are more complicated than
others. Try your hand at encoding a message. Here are some strategies you might
want to use.
Codebreakers
NOVAactivity
1 Think of a ?secret password? in which no letter of the alphabet is used more than
once. Write the password. Then write the rest of the alphabet, but leave out all the
letters in the password. So, if the password is GOTHIC, what you write would look
like this:
G
O
T
H
I
C
A
B
D
E
F
J
K
L
M
N
P
Q
R
S
U
V
W
X
Y
Z
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Write the alphabet in order under the password alphabet to see which letter stands
for what.
Using this cipher, the word A P P L E would read G Q Q N J.
2 Create a matrix like the one below.
1
2
3
4
5
1
A
B
C
D
E
2
F
G
H
I-J
K
3
L
M
N
O
P
4
Q
R
S
T
U
5
V
W
X
Y
Z
To encode a message, replace each letter with a two-digit number ? the number of
the row and number of the column where the letter is found. For example, the word
APPLE would read:
A P P L E
11 35 35 31 15, or
1135353115.
3 Create a complex cipher based on the above grid, but with significant alterations
to help hide the letter frequencies. In the following case, each letter of each word in a
message comes from a different cipher. (Each cipher is designated by a number.)
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
S
T
U
V
W
X
Y
Z
1
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
T
U
V
W
X
Y
Z
A
2
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
U
V
W
X
Y
Z
A
B
3
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
V
W
X
Y
Z
A
B
C
(and so on)
So the phrase APPLES ARE GOOD might be represented as follows:
A P P L
B R S M
E S A R E G O O D
F U D S H H Q R E
Note that the repeated letters, a, p, and o, are not represented by the same cipher
letter and that in some cases, the same cipher letter stands for two different letters
(H = e and g; S= p and r; R = p and o).
4 Write your own coded message here.
Made possible by a grant from Lockheed
7
Letter
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
How many times does it appear in the text
…
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