WGU C839 EXAM INTRODUCTION TO
CRYPTOGRAPHY EXAM | ALL QUESTIONS
AND CORRECT ANSWERS | VERIFIED
ANSWERS | LATEST VERSION (JUST
RELEASED)
Used to authenticate to the server. Contains the identity of the client, the
session key, the timestamp, and the checksum. It is encrypted with the
server's key. ------CORRECT ANSWER---------------Ticket
____________ uses the stream cipher RC4 (128 bit or 256 bit). For a 24-bit
IV, there is a 50% probability the same IV will repeat after 5000 packets ----
--CORRECT ANSWER---------------WEP (Wired Equivalent Privacy)
_____ was developed by Netscape and has since been supplanted by TLS.
It was the preferred method used with secure websites (i.e. https). ------
CORRECT ANSWER---------------SSL
_________________ is a protocol for encrypting transmissions. A client
and server negotiate a connection by using a handshaking procedure, in
which the client and server agree on various parameters used to establish
the connection's security. ------CORRECT ANSWER---------------Transport
Layer Security (TLS)
Microsoft provides a system for encrypting partitions or entire hard drives
using a Trusted Platform Module (TPM). By default, it uses the AES
,encryption algorithm with a 128-bit key. ------CORRECT ANSWER------------
---Bitlocker
_________________ is the art and science of writing hidden messages in
such a way that no one, apart from the sender and intended recipient,
suspects the existence of the message. It is a form of security through
obscurity. By altering the least significant bit, one can hide additional data
without altering the original file in any noticeable way. ------CORRECT
ANSWER---------------Steganography
Payload - The data to be covertly communicated, the message you wish to
hide
Carrier - The signal, stream, or data file into which the payload is hidden
Channel - The type of medium used. This may be still photos, video, or
sound files ------CORRECT ANSWER---------------Steganography Terms
The most common steganography method is _____________________. ---
---CORRECT ANSWER---------------Least Significant Bits (LSB)
This method of Audio Steganography (Steganophony) adds an extra sound
to an echo inside an audio file, that extra sound conceals information. ------
CORRECT ANSWER---------------Echo hiding
The NSA classifies Suite A cryptographies as published, while Suite B as
not published. NSA Suite A cryptography contains classified algorithms that
will not be released. These algorithms are used to encrypt especially
sensitive information. Suite B are publically described algorithms.
,A True
B False ------CORRECT ANSWER---------------A
This is the most basic tool for breaking most classical ciphers. In natural
languages, certain letters of the alphabet appear more frequently than
others. By examining those frequencies, you can derive some information
about the key that was used. This method is very effective against classic
ciphers like Caesar, Vigenère, etc. It is far less effective against modern
methods. ------CORRECT ANSWER---------------Frequency Analysis
In a ____________________, the attacker obtains the ciphertexts
corresponding to a set of plaintexts. This can allow the attacker to attempt
to derive the key used and thus decrypt other messages encrypted with
that key. ------CORRECT ANSWER---------------Chosen plaintext attack
A ____________________ is less effective, but much more likely for the
attacker since the attacker only has access to a collection of ciphertexts.
NOTE: The attacker ONLY has access to the ciphertext of messages. ------
CORRECT ANSWER---------------Ciphertext-only attack
The __________________ is similar to the chosen-plaintext attack, except
the attacker can obtain ciphertexts encrypted under two different keys. (the
keys need to be related, meaning that one was derived from the other as is
the case in wireless systems) ------CORRECT ANSWER---------------
Related-key attack
A known-plaintext attack and uses a linear approximation to describe the
behavior of the block cipher.
, Given sufficient pairs of plaintext and corresponding ciphertext, bits of
information about the key can be obtained and increased amounts of data
will usually give a higher probability of success.
Invented by Mitsarue Matsui. ------CORRECT ANSWER---------------Linear
Cryptanalysis
__________________ is a form of cryptanalysis applicable to symmetric
key algorithms and was invented by Eli Biham and Adi Shamir.
Essentially, it is the examination of differences in an input and how that
affects the resultant difference in the output. It originally worked only with
chosen plaintext.
It could also work with known plaintext and ciphertext. ------CORRECT
ANSWER---------------Differential cryptanalysis
Similar to Differential Cryptanalysis, but uses a different technique.
Uses sets or even multisets of chosen plaintexts of which part is held
constant and another part varies through all possibilities. ------CORRECT
ANSWER---------------Integral cryptanalysis
The attacker deduces the secret key. ------CORRECT ANSWER---------------
Total break
The attacker discovers a functionally equivalent algorithm for encryption
and decryption, but without learning the key. ------CORRECT ANSWER-----
----------Global deduction
CRYPTOGRAPHY EXAM | ALL QUESTIONS
AND CORRECT ANSWERS | VERIFIED
ANSWERS | LATEST VERSION (JUST
RELEASED)
Used to authenticate to the server. Contains the identity of the client, the
session key, the timestamp, and the checksum. It is encrypted with the
server's key. ------CORRECT ANSWER---------------Ticket
____________ uses the stream cipher RC4 (128 bit or 256 bit). For a 24-bit
IV, there is a 50% probability the same IV will repeat after 5000 packets ----
--CORRECT ANSWER---------------WEP (Wired Equivalent Privacy)
_____ was developed by Netscape and has since been supplanted by TLS.
It was the preferred method used with secure websites (i.e. https). ------
CORRECT ANSWER---------------SSL
_________________ is a protocol for encrypting transmissions. A client
and server negotiate a connection by using a handshaking procedure, in
which the client and server agree on various parameters used to establish
the connection's security. ------CORRECT ANSWER---------------Transport
Layer Security (TLS)
Microsoft provides a system for encrypting partitions or entire hard drives
using a Trusted Platform Module (TPM). By default, it uses the AES
,encryption algorithm with a 128-bit key. ------CORRECT ANSWER------------
---Bitlocker
_________________ is the art and science of writing hidden messages in
such a way that no one, apart from the sender and intended recipient,
suspects the existence of the message. It is a form of security through
obscurity. By altering the least significant bit, one can hide additional data
without altering the original file in any noticeable way. ------CORRECT
ANSWER---------------Steganography
Payload - The data to be covertly communicated, the message you wish to
hide
Carrier - The signal, stream, or data file into which the payload is hidden
Channel - The type of medium used. This may be still photos, video, or
sound files ------CORRECT ANSWER---------------Steganography Terms
The most common steganography method is _____________________. ---
---CORRECT ANSWER---------------Least Significant Bits (LSB)
This method of Audio Steganography (Steganophony) adds an extra sound
to an echo inside an audio file, that extra sound conceals information. ------
CORRECT ANSWER---------------Echo hiding
The NSA classifies Suite A cryptographies as published, while Suite B as
not published. NSA Suite A cryptography contains classified algorithms that
will not be released. These algorithms are used to encrypt especially
sensitive information. Suite B are publically described algorithms.
,A True
B False ------CORRECT ANSWER---------------A
This is the most basic tool for breaking most classical ciphers. In natural
languages, certain letters of the alphabet appear more frequently than
others. By examining those frequencies, you can derive some information
about the key that was used. This method is very effective against classic
ciphers like Caesar, Vigenère, etc. It is far less effective against modern
methods. ------CORRECT ANSWER---------------Frequency Analysis
In a ____________________, the attacker obtains the ciphertexts
corresponding to a set of plaintexts. This can allow the attacker to attempt
to derive the key used and thus decrypt other messages encrypted with
that key. ------CORRECT ANSWER---------------Chosen plaintext attack
A ____________________ is less effective, but much more likely for the
attacker since the attacker only has access to a collection of ciphertexts.
NOTE: The attacker ONLY has access to the ciphertext of messages. ------
CORRECT ANSWER---------------Ciphertext-only attack
The __________________ is similar to the chosen-plaintext attack, except
the attacker can obtain ciphertexts encrypted under two different keys. (the
keys need to be related, meaning that one was derived from the other as is
the case in wireless systems) ------CORRECT ANSWER---------------
Related-key attack
A known-plaintext attack and uses a linear approximation to describe the
behavior of the block cipher.
, Given sufficient pairs of plaintext and corresponding ciphertext, bits of
information about the key can be obtained and increased amounts of data
will usually give a higher probability of success.
Invented by Mitsarue Matsui. ------CORRECT ANSWER---------------Linear
Cryptanalysis
__________________ is a form of cryptanalysis applicable to symmetric
key algorithms and was invented by Eli Biham and Adi Shamir.
Essentially, it is the examination of differences in an input and how that
affects the resultant difference in the output. It originally worked only with
chosen plaintext.
It could also work with known plaintext and ciphertext. ------CORRECT
ANSWER---------------Differential cryptanalysis
Similar to Differential Cryptanalysis, but uses a different technique.
Uses sets or even multisets of chosen plaintexts of which part is held
constant and another part varies through all possibilities. ------CORRECT
ANSWER---------------Integral cryptanalysis
The attacker deduces the secret key. ------CORRECT ANSWER---------------
Total break
The attacker discovers a functionally equivalent algorithm for encryption
and decryption, but without learning the key. ------CORRECT ANSWER-----
----------Global deduction
