WGU Course C839 - Intro to Cryptography Exam Questions with Correct Answers| Latest
Update Guaranteed Success
______________ is the simplest form of authentication where the user's name and password
are transmitted over a network and compared to a table of name-password pairs. Typically, the
passwords stored in the table are encrypted; however, the transmissions of the passwords are
in cleartext, unencrypted. This is it's main weakness. The Basic Authentication feature built into
HTTP uses this form of authentication. Password Authentication Protocol (PAP)
____________________________ calculates a hash after the user has logged in, then it shares
that hash with the client system. Periodically, the server will ask the client to provide that hash
(this is the challenge part). If the client cannot, then it is clear that the communications have
been compromised. Challenge HandShake Authentication Protocol (CHAP)
____________is used widely, particularly with Microsoft operating systems. It was invented at
MIT and derives its name from the mythical three-headed dog that was reputed to guard the
gates of Hades. The client authenticates to the authentication server once using a long-term
shared secret (e.g. a password) and receives a ticket-granting server from the authentication
server.
The tickets are time-stamped. This allows you to make additional requests using the same ticket
within a certain time period (typically, eight hours).
Uses symmetric cryptography
Authentication is UDP port 88 Kerberos
A server or client that Kerberos can assign tickets to. Basically, any machine that can be
assigned tickets is known as a _____________________. Principal
,A server that authorizes the principal and connects them to the ticket granting server.
Authentication Server (AS)
Provides tickets Ticket Granting Server (TGS)
The ticket that is granted during the authentication process. Ticket Granting Ticket (TGT)
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. 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 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). 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. 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.
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. 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
Steganography Terms
The most common steganography method is _____________________. 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. 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 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.
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. 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. 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) 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. 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. Differential cryptanalysis
Update Guaranteed Success
______________ is the simplest form of authentication where the user's name and password
are transmitted over a network and compared to a table of name-password pairs. Typically, the
passwords stored in the table are encrypted; however, the transmissions of the passwords are
in cleartext, unencrypted. This is it's main weakness. The Basic Authentication feature built into
HTTP uses this form of authentication. Password Authentication Protocol (PAP)
____________________________ calculates a hash after the user has logged in, then it shares
that hash with the client system. Periodically, the server will ask the client to provide that hash
(this is the challenge part). If the client cannot, then it is clear that the communications have
been compromised. Challenge HandShake Authentication Protocol (CHAP)
____________is used widely, particularly with Microsoft operating systems. It was invented at
MIT and derives its name from the mythical three-headed dog that was reputed to guard the
gates of Hades. The client authenticates to the authentication server once using a long-term
shared secret (e.g. a password) and receives a ticket-granting server from the authentication
server.
The tickets are time-stamped. This allows you to make additional requests using the same ticket
within a certain time period (typically, eight hours).
Uses symmetric cryptography
Authentication is UDP port 88 Kerberos
A server or client that Kerberos can assign tickets to. Basically, any machine that can be
assigned tickets is known as a _____________________. Principal
,A server that authorizes the principal and connects them to the ticket granting server.
Authentication Server (AS)
Provides tickets Ticket Granting Server (TGS)
The ticket that is granted during the authentication process. Ticket Granting Ticket (TGT)
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. 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 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). 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. 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.
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. 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
Steganography Terms
The most common steganography method is _____________________. 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. 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 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.
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. 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. 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) 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. 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. Differential cryptanalysis
