Question 1

One of the most secure algorithms for encryption today is called:

Accepted Answer

A)  brute force. 
B)  RSA. 
C)  the Turing cipher. 
D)  the rail fence cipher. 
A)  brute force. 
B)  RSA. 
C)  the Turing cipher. 
D)  the rail fence cipher. B

Question 2

Briefly describe how to crack a substitution cipher.

Accepted Answer

The substitution cipher is much harder to crack than the rail fence cipher. There are 26!, or roughly 4 × 10²⁶, different possible arrangements of the alphabet that could be used as a key. Clearly, the brute force strategy for finding the key would take an extremely long time. However, the substitution cipher does have a fatal flaw that we can exploit. The flaw is that the substitution cipher allows us to take advantage of patterns in the English language that help us deduce letters in the key. The first pattern to exploit is that some letters in the English language appear more frequently than others. If we count the number of times each letter occurs in a document such as this book, or any other English language book, we would find that the letters e, t, a, o, and i are much more common than many other letters in the alphabet. Using regular expressions can also help to fill in letters of a word in the ciphertext.

Question 3

Describe the function of regular expressions and explain how to use them in Python.

Accepted Answer

Regular expressions allow us to see if two strings match, much like the ==, except that in regular expressions, we can use wild card characters as part of the match. For example, we can test to see if the string .ADE matched FADE. When using regular expressions, the . character is a wildcard that matches any character. The regular expression function that we use to test if two strings match is called match. The match function takes two parameters: a regular expression and the string we want to match against.

Question 4

What are the benefits of using a dictionary over a list when looking up values?

Accepted Answer

The answer is speed. Suppose you rewrote

Question 5

____ order takes the first row of the table and stores all the values on that row one after the other, followed by the second row and the third, and so on.

Accepted Answer

A)  Column major 
B)  Row major 
C)  Encrypted 
D)  Rail post 
A)  Column major 
B)  Row major 
C)  Encrypted 
D)  Rail post

Question 6

Using the setDefault pattern is efficient for adding values to a dictionary.

Accepted Answer

A) True 
 B)False

Question 7

If we want to store a two-dimensional table in a computer's memory, we need to map from the row, column coordinates, which correspond to a cell in the table, to a location in memory.

Accepted Answer

A) True 
 B)False

Question 8

Describe the use of brute force to decrypt encrypted messages.

Accepted Answer

Breaking advanced codes by brute force i

Question 9

Match each definition with its term.
-Allow us to determine what characters in a target word match letters in different
Parts of a given pattern.

Accepted Answer

A)  Regular expression 
B)  Cryptanalysis 
C)  Capture group 
D)  Brute force 
A)  Regular expression 
B)  Cryptanalysis 
C)  Capture group 
D)  Brute force

Question 10

What of the following is one of the most frequently occurring letters in the English language?

Accepted Answer

A)  B 
B)  E 
C)  U 
D)  S 
A)  B 
B)  E 
C)  U 
D)  S

Question 11

Case Study 2:
1. def maybeAdd(ch, toList):
2. if ch in 'abcdefghijklmnopqrstuvwxyz'
and ch not in toList:
3. toList.append (ch)
-Refer to the session in the accompanying Case Study 2. What is the value of myList after the following code is executed?
>>> myList
['a', 'b']
>>> maybeAdd('a', myList)

Accepted Answer

A)  ['a', 'a', 'b'] 
B)  ['a', 'b'] 
C)  ['abcdefghijklmnopqrstuvwxyz'] 
D)  None 
A)  ['a', 'a', 'b'] 
B)  ['a', 'b'] 
C)  ['abcdefghijklmnopqrstuvwxyz'] 
D)  None

Question 12

Case Study 1:
1. def railBreak(cipherText):
2. wordDict = createWordDict('wordlist.txt')
3. cipherLen = len(cipherText)
4. maxGoodSoFar = 0
5. bestGuess = "No words found in dictionary"
6. for i in range(2, cipherLen + 1):
7. words = railDecrypt(cipherText, i)
8. goodCount = 0
9. for w in words:
10. if w in wordDict:
11. goodCount = goodCount + 1
12. if goodCount > maxGoodSoFar:
13. maxGoodSoFar = goodCount
14. bestGuess = " ".join(words)
15. return bestGuess
-Refer to the session in the accompanying case study. What is the function of
" ")join(words) on line 14?

Accepted Answer

A)  It glues together all of the strings in the list words separating them using the space character. 
B)  It creates a dictionary of all the words in the list words. 
C)  It separates each word in the list words into a range. 
D)  It sets all of the values in words to a single space. 
A)  It glues together all of the strings in the list words separating them using the space character. 
B)  It creates a dictionary of all the words in the list words. 
C)  It separates each word in the list words into a range. 
D)  It sets all of the values in words to a single space.

Question 13

Describe the use of the join method.

Accepted Answer

The expression " ".join(words) returns a

Question 14

How can a dictionary be used to improve upon a brute force approach to decrypting a rail fence cipher?

Accepted Answer

The problem with the brute force approac

Question 15

Describe the two keyword parameters to the sort method.

Accepted Answer

There are two keyword parameters for the

Question 16

Match each definition with its term.
-Refers to trying all possible solutions.

Accepted Answer

A)  Regular expression 
B)  Cryptanalysis 
C)  Capture group 
D)  Brute force 
A)  Regular expression 
B)  Cryptanalysis 
C)  Capture group 
D)  Brute force

Question 17

Case Study 1:
1. def railBreak(cipherText):
2. wordDict = createWordDict('wordlist.txt')
3. cipherLen = len(cipherText)
4. maxGoodSoFar = 0
5. bestGuess = "No words found in dictionary"
6. for i in range(2, cipherLen + 1):
7. words = railDecrypt(cipherText, i)
8. goodCount = 0
9. for w in words:
10. if w in wordDict:
11. goodCount = goodCount + 1
12. if goodCount > maxGoodSoFar:
13. maxGoodSoFar = goodCount
14. bestGuess = " ".join(words)
15. return bestGuess
-Refer to the session in the accompanying Case Study 1. What pattern is used on lines 12-14?

Accepted Answer

A)  Minmax 
B)  Rail break 
C)  Cryptology 
D)  Brute force 
A)  Minmax 
B)  Rail break 
C)  Cryptology 
D)  Brute force

Question 18

What three-letter word appears most often in War of the Worlds?

Accepted Answer

A)  The 
B)  And 
C)  Was 
D)  Had 
A)  The 
B)  And 
C)  Was 
D)  Had

Question 19

Explain how to identify the difference between vowels and consonants in the English language.

Accepted Answer

One way that we can statistically tell t

Question 20

Some of the first computer scientists were deeply involved in cryptanalysis.

Accepted Answer

A) True 
 B)False

One of the most secure algorithms for encryption today is called:

Briefly describe how to crack a substitution cipher.

Describe the function of regular expressions and explain how to use them in Python.

What are the benefits of using a dictionary over a list when looking up values?

____ order takes the first row of the table and stores all the values on that row one after the other, followed by the second row and the third, and so on.

Using the setDefault pattern is efficient for adding values to a dictionary.

If we want to store a two-dimensional table in a computer's memory, we need to map from the row, column coordinates, which correspond to a cell in the table, to a location in memory.

Describe the use of brute force to decrypt encrypted messages.

Match each definition with its term. -Allow us to determine what characters in a target word match letters in different Parts of a given pattern.

What of the following is one of the most frequently occurring letters in the English language?

Case Study 2: 1. def maybeAdd(ch, toList): 2. if ch in 'abcdefghijklmnopqrstuvwxyz' and ch not in toList: 3. toList.append (ch) -Refer to the session in the accompanying Case Study 2. What is the value of myList after the following code is executed? >>> myList ['a', 'b'] >>> maybeAdd('a', myList)

Describe the use of the join method.

How can a dictionary be used to improve upon a brute force approach to decrypting a rail fence cipher?

Describe the two keyword parameters to the sort method.

Match each definition with its term. -Refers to trying all possible solutions.

What three-letter word appears most often in War of the Worlds?

Explain how to identify the difference between vowels and consonants in the English language.

Some of the first computer scientists were deeply involved in cryptanalysis.

Introduction to Python: Introduction to Numeric Types, Turtle Graphics, Simple for Loops and Functions

Pthon: Estimating PI: Math and Random Methods, Selection and Boolean Expressions, the Print Function

Codes and Other Secrets: String Operators and Methods, the Len Built-In Function, Keyword Parameters, User Input

Introducing the Python Collections: Lists, Dictionaries, Tuples, and Statistics

Bigger Data: File Io: the While Loop, String Formatting, Reading Online Data in CSV and Json Formats

Image Processing: Nested for Loops, Functions As Parameters, Namespaces, Lists of Lists

Data Mining: Cluster Analysis: More on the While Loop; Parrallel Lists

Fractals: the Geometry of Nature: Recursion, Grammars and Production Rules

Astronomy: Creating Classes, Writing Constructors, Accessors, Mutators and Special Methods

Simulation:computer Simulation Using Objects

Father Was a Rectangle: Inheritance and Object-Oriented Design

Video Games: Multithreading, Event Handlers, Static Variables

Filters

Exam 8: Cryptanalysis: Advanced Dictionaries and Lists, Regular Expressions

One of the most secure algorithms for encryption today is called:

Briefly describe how to crack a substitution cipher.

Describe the function of regular expressions and explain how to use them in Python.

What are the benefits of using a dictionary over a list when looking up values?

____ order takes the first row of the table and stores all the values on that row one after the other, followed by the second row and the third, and so on.

Using the setDefault pattern is efficient for adding values to a dictionary.

If we want to store a two-dimensional table in a computer's memory, we need to map from the row, column coordinates, which correspond to a cell in the table, to a location in memory.

Describe the use of brute force to decrypt encrypted messages.

Match each definition with its term. -Allow us to determine what characters in a target word match letters in different Parts of a given pattern.

What of the following is one of the most frequently occurring letters in the English language?

Case Study 2: 1. def maybeAdd(ch, toList): 2. if ch in 'abcdefghijklmnopqrstuvwxyz' and ch not in toList: 3. toList.append (ch) -Refer to the session in the accompanying Case Study 2. What is the value of myList after the following code is executed? >>> myList ['a', 'b'] >>> maybeAdd('a', myList)

Describe the use of the join method.

How can a dictionary be used to improve upon a brute force approach to decrypting a rail fence cipher?

Describe the two keyword parameters to the sort method.

Match each definition with its term. -Refers to trying all possible solutions.

What three-letter word appears most often in War of the Worlds?

Explain how to identify the difference between vowels and consonants in the English language.

Some of the first computer scientists were deeply involved in cryptanalysis.

Introduction to Python: Introduction to Numeric Types, Turtle Graphics, Simple for Loops and Functions

Pthon: Estimating PI: Math and Random Methods, Selection and Boolean Expressions, the Print Function

Codes and Other Secrets: String Operators and Methods, the Len Built-In Function, Keyword Parameters, User Input

Introducing the Python Collections: Lists, Dictionaries, Tuples, and Statistics

Bigger Data: File Io: the While Loop, String Formatting, Reading Online Data in CSV and Json Formats

Image Processing: Nested for Loops, Functions As Parameters, Namespaces, Lists of Lists

Data Mining: Cluster Analysis: More on the While Loop; Parrallel Lists

Fractals: the Geometry of Nature: Recursion, Grammars and Production Rules

Astronomy: Creating Classes, Writing Constructors, Accessors, Mutators and Special Methods

Simulation:computer Simulation Using Objects

Father Was a Rectangle: Inheritance and Object-Oriented Design

Video Games: Multithreading, Event Handlers, Static Variables

Filters