The Game 8 groups of 2 5 rounds Basic Definitions Substitution Cryptosystems Math Tricky Questions Comparing Cryptosystems 10 questions per round Each question is worth 1 point Basic Definitions ID: 564199
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Slide1
Cryptography TriviaSlide2
The Game
8 groups of 2
5 rounds
Basic
Definitions
Substitution Cryptosystems
Math
Tricky Questions
Comparing Cryptosystems
10 questions per round
Each question is worth 1 pointSlide3
Basic Definitions
Alice and Bob should at some point have access to a ________ mode of communication.
Cryptography is only needed when a message is both _______ and ________.
To determine how difficult a cryptosystem is to break, we measure its ________.
To determine how quickly a cryptosystem operates, we measure its ________.Slide4
Basic Definitions
_______ is the science of keeping information secure even though it is transmitted through an insecure medium.
_______ is the science of breaking ciphers.
A _______ is a matching between two different alphabets.
To break a cipher means to determine the ______.
A cryptosystem is made up of five parts: plaintext space, ciphertext space, encryption function, decryption function, and __________.Slide5
Substitution
Cryptosystems
A substitution cipher uses this to represent its key.
A rotation cipher uses this to represent its key.
An affine cipher uses this to represent its key.
How many possible keys does a substitution cipher on
have?
How many possible keys does a rotation cipher on
have?
Slide6
Substitution
Cryptosystems
How many possible keys does an affine cipher on
have?
Encrypt
using a rotation cipher over
with
.
Encrypt
using an affine cipher over
with
Cipher X consists of a rotation, and then an affine cipher. What type of cipher is X?
Cipher Y is a substitution cipher over . Cipher consists of applying Y twenty-four times. What type of cipher is X? Be as specific as possible.
Slide7
Math
Find
in
.
Find
in
.
Find
in
.
Find
in
.Find .Solve
for
and
.Solve the pair and for and .For what is invertible in ?Find the prime factorization of 142.Find in .
Slide8
Tricky Questions
Which of these is a faster growth rate:
or
?
Which of these is a faster growth rate:
or
?
Approximately how many primes are there between 100,000 and 1,000,000?
Find a rotation cipher with more keys than a substitution cipher.
What is the maximum number of solutions that
can have over
. (
are constants,
is the variable)
Slide9
Tricky Questions
A substitution cipher over
has a key sorted by plaintext. During decryption, how many table-lookups are required in the worst case?
A
substitution cipher over
has a key sorted by plaintext.
4 different characters are encrypted. How
many table-lookups are required in the
worst
case?How many possible Vigenere ciphers over
are there that can encrypt exactly 3 characters?
A one-time-pad is used on a 5 character message. Oscar figured out the keys, but not the order. In the worst case, how many guesses must be try before deciphering the message?
How many factors does 1,000,000 have? Slide10
Comparing Cryptosystems
Among Rotation, Affine, and
A
utokey
, which is most resistant to a known-plaintext attack?
Among Affine,
Autokey
, and
Vigenere
, which can encrypt the fastest?Among Affine, Autokey, and Vigenere, which can decrypt the fastest?Which has a larger keyspace? Affine over
or
Vigenere
over ? Which has a larger keysize? Substitution over or rotation over
Slide11
Comparing Cryptosystems
Which is more secure? Affine or a
Vigenere
ciphers?
Which is more secure?
Vigenere
or Hill ciphers?
Could a computer with 4 processors perform 200 Rotation encryptions or 100
Autokey
encryptions faster?Could a computer with 4 processors perform 200 Rotation encryptions or 100 Affine encryptions faster?Which has a larger keyspace? Hill over
or
Vigenere
over ? Slide12
Cryptography Trivia
The EndSlide13
Reference Information
Created in the summer of 2013 by Dr. Jeffrey
Beyerl
for use in a cryptography class.
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