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WGU C839 - Intro to Cryptography Exam 2022
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completely Solved 100 Q&A GRADED A+
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The most widely used asymmetric encryption algorithm is what?
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A RSA
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B Vigenere
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C DES
D Caesar Cipher - Answer A
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Original, unencrypted information is referred to as ____.
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A text la
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B plaintext
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C cleantext
D ciphertext - Answer B
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Which of the following is NOT an asymmetric system?
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A PGP
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B RSA
C SSL
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D DES - Answer D
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In order for User A to send User B an encrypted message that only User B can read,
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User A must encrypt message with which of the following keys?
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A User A's public key
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B User A's private key
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C User B's public key
D User B's private key - Answer C
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The greatest weakness with symmetric algorithms is _____.
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A They are less secure than asymmetric
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B The problem of key exchange
C They are slower than asymmetric
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D The problem of generating keys - Answer B
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Which of the following is generally true about block sizes?
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A Smaller block sizes increase security
B Block sizes must be more than 256 bits to be secure
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C Block size is irrelevant to security
D Larger block sizes increase security - Answer D
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A _____ is a function that takes a variable-size input m and returns a fixed-size
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string.
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A Symmetric cipher
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B Hash
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C Asymmetric cipher
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D Feistel - Answer B
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Which of the following is a cryptographic protocol that allows two parties to establish
a shared key over an insecure channel?
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A Elliptic Curve
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B RSA
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C MD5
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D Diffie-Hellman - Answer D
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A _________ is a digital representation of information that identifies you as a
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relevant entity by a trusted third party?
A Digital Signature
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B Hash
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C Ownership stamp
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D Digest - Answer A
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What is the standard used by most digital certificates? z
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A X.509
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B CRL
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C RFC 2298
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D OCSP - Answer A
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DES uses keys of what size?
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A 56 bits
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B 192 bits
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C 128 bits
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D 64 bits - Answer A
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Which of the following is NOT a key size used by AES?
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A 512 bits
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B 128 bits
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C 192 bits
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Which of the following was a multi alphabet cipher widely used from the 16th century
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A Vigenere
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B Caesar
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C Atbash
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D Scytale - Answer A
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Which of the following is a substitution cipher used by ancient Hebrew scholars?
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A Caesar
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B Vigenere
C Scytale
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D Atbash - Answer D
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Shifting each letter in the alphabet a fixed number of spaces to the right or left is an
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example of what?
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A Bit shifting
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B Confusion
C Multi substitution
D Single substitution - Answer D la
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Which of the following most accurately defines encryption?
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A changing a message so it can only be easily read by the intended recipient
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B Making binary changes to a message to conceal it
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D Applying keys to plain text - Answer A
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If you use substitution alone, what weakness is present in the resulting cipher text?
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A It is the same length as the original text
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C It is too simple.
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D Because it maintains letter and word frequency. - Answer D
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_____ uses at least two different shifts, changing the shift with different letters in the
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plain text.
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A Atbash
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B multi-alphabet encryption
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C Scytale
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D Caesar cipher - Answer B
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____ was designed to provide built in cryptography for the clipper chip.
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A Blowfish
B Skipjack
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C GOST
D 3DES - Answer B
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Which of the following uses an 80 bit key on 64 bit blocks?
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A Twofish
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B AES
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C Skipjack
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D DES - Answer C
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With _____, the message is divided into blocks and each block is encrypted
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separately. This is the most basic mode for symmetric encryption.
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A Electronic codebook (ECB)
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B Cipher-block chaining (CBC)
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C Cipher feedback (CFB)
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D Output feedback (OFB) - Answer A
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Which of the following is an example of an unbalanced Feistel?
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A 3DES
B Skipjack
C Twofish
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D AES - Answer B
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This process is done by having each block of plaintext is XORed with the previous
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ciphertext block before being encrypted.
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A Output feedback (OFB)
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B Cipher-block chaining (CBC)
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C Electronic codebook (ECB)
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D Cipher feedback (CFB) - Answer B
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The process wherein the ciphertext block is encrypted then the ciphertext produced
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what?
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A Output feedback (OFB)
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B Cipher-block chaining (CBC)
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C Cipher feedback (CFB)
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D Electronic codebook (ECB) - Answer C
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This is a method for turning a block cipher into a stream cipher by generating a
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keystream block, which are then XORed with the plaintext blocks to get the
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ciphertext.
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WGU C839 - Intro to Cryptography Exam 2022
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completely Solved 100 Q&A GRADED A+
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The most widely used asymmetric encryption algorithm is what?
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A RSA
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B Vigenere
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C DES
D Caesar Cipher - Answer A
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Original, unencrypted information is referred to as ____.
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A text la
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B plaintext
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C cleantext
D ciphertext - Answer B
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Which of the following is NOT an asymmetric system?
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A PGP
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B RSA
C SSL
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D DES - Answer D
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In order for User A to send User B an encrypted message that only User B can read,
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User A must encrypt message with which of the following keys?
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A User A's public key
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B User A's private key
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C User B's public key
D User B's private key - Answer C
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The greatest weakness with symmetric algorithms is _____.
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A They are less secure than asymmetric
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B The problem of key exchange
C They are slower than asymmetric
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D The problem of generating keys - Answer B
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Which of the following is generally true about block sizes?
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A Smaller block sizes increase security
B Block sizes must be more than 256 bits to be secure
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C Block size is irrelevant to security
D Larger block sizes increase security - Answer D
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A _____ is a function that takes a variable-size input m and returns a fixed-size
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string.
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A Symmetric cipher
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B Hash
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C Asymmetric cipher
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D Feistel - Answer B
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Which of the following is a cryptographic protocol that allows two parties to establish
a shared key over an insecure channel?
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A Elliptic Curve
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B RSA
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C MD5
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D Diffie-Hellman - Answer D
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A _________ is a digital representation of information that identifies you as a
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relevant entity by a trusted third party?
A Digital Signature
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B Hash
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C Ownership stamp
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D Digest - Answer A
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What is the standard used by most digital certificates? z
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A X.509
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B CRL
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C RFC 2298
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D OCSP - Answer A
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DES uses keys of what size?
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A 56 bits
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B 192 bits
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C 128 bits
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D 64 bits - Answer A
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Which of the following is NOT a key size used by AES?
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A 512 bits
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B 128 bits
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C 192 bits
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l D 256 bits - Answer A a
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Which of the following was a multi alphabet cipher widely used from the 16th century
(1553) to the early 20th century (1900s)?
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A Vigenere
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B Caesar
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C Atbash
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D Scytale - Answer A
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Which of the following is a substitution cipher used by ancient Hebrew scholars?
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A Caesar
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B Vigenere
C Scytale
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D Atbash - Answer D
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Shifting each letter in the alphabet a fixed number of spaces to the right or left is an
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example of what?
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A Bit shifting
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B Confusion
C Multi substitution
D Single substitution - Answer D la
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Which of the following most accurately defines encryption?
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A changing a message so it can only be easily read by the intended recipient
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B Making binary changes to a message to conceal it
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C changing a message using complex mathematics z
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D Applying keys to plain text - Answer A
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If you use substitution alone, what weakness is present in the resulting cipher text?
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A It is the same length as the original text
B It is easily broken with modern computers.
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C It is too simple.
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D Because it maintains letter and word frequency. - Answer D
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_____ uses at least two different shifts, changing the shift with different letters in the
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plain text.
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A Atbash
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B multi-alphabet encryption
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C Scytale
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D Caesar cipher - Answer B
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____ was designed to provide built in cryptography for the clipper chip.
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A Blowfish
B Skipjack
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C GOST
D 3DES - Answer B
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Which of the following uses an 80 bit key on 64 bit blocks?
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A Twofish
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B AES
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C Skipjack
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D DES - Answer C
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With _____, the message is divided into blocks and each block is encrypted
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separately. This is the most basic mode for symmetric encryption.
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A Electronic codebook (ECB)
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B Cipher-block chaining (CBC)
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C Cipher feedback (CFB)
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D Output feedback (OFB) - Answer A
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Which of the following is an example of an unbalanced Feistel?
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A 3DES
B Skipjack
C Twofish
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D AES - Answer B
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This process is done by having each block of plaintext is XORed with the previous
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ciphertext block before being encrypted.
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A Output feedback (OFB)
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B Cipher-block chaining (CBC)
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C Electronic codebook (ECB)
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D Cipher feedback (CFB) - Answer B
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The process wherein the ciphertext block is encrypted then the ciphertext produced
is XOR'd back with the plaintext to produce the current ciphertext block is called
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what?
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sh
A Output feedback (OFB)
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B Cipher-block chaining (CBC)
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C Cipher feedback (CFB)
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D Electronic codebook (ECB) - Answer C
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This is a method for turning a block cipher into a stream cipher by generating a
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keystream block, which are then XORed with the plaintext blocks to get the
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ciphertext.
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