Intro to Cryptography /WGU Course C839 - (2025) ACTUAL
EXAM (TESTING REAL EXAM QUESTIONS) AND VERIFIED
ANSWERS (MULTIPLE CHOICES) |COMPLETE SOLUTIONS
|A+ GRADED |100% CORRECT!!
What type of encryption uses different keys to encrypt and decrypt the message?
A Symmetric
B Private key
C Secure
D Asymmetric
D
The most widely used asymmetric encryption algorithm is what?
A RSA
B Vigenere
C DES
D Caesar Cipher
A
Original, unencrypted information is referred to as ____.
A text
B plaintext
C cleantext
D ciphertext
B
Which of the following is NOT an asymmetric system?
A PGP
B RSA
C SSL
D DES
D
1|Page
,In order for User A to send User B an encrypted message that only User B can read, User A must
encrypt message with which of the following keys?
A User A's public key
B User A's private key
C User B's public key
D User B's private key
C
The greatest weakness with symmetric algorithms is _____.
A They are less secure than asymmetric
B The problem of key exchange
C They are slower than asymmetric
D The problem of generating keys
B
Which of the following is generally true about block sizes?
A Smaller block sizes increase security
B Block sizes must be more than 256 bits to be secure
C Block size is irrelevant to security
D Larger block sizes increase security
D
A _____ is a function that takes a variable-size input m and returns a fixed-size string.
A Symmetric cipher
B Hash
C Asymmetric cipher
D Feistel
B
Which of the following is a cryptographic protocol that allows two parties to establish a shared
key over an insecure channel?
A Elliptic Curve
B RSA
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,C MD5
D Diffie-Hellman
D
A _________ is a digital representation of information that identifies you as a relevant entity by
a trusted third party?
A Digital Signature
B Hash
C Ownership stamp
D Digest
A
What is the standard used by most digital certificates?
A X.509
B CRL
C RFC 2298
D OCSP
A
DES uses keys of what size?
A 56 bits
B 192 bits
C 128 bits
D 64 bits
A
Which of the following is NOT a key size used by AES?
A 512 bits
B 128 bits
C 192 bits
D 256 bits
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)?
A Vigenere
B Caesar
C Atbash
D Scytale
A
Which of the following is a substitution cipher used by ancient Hebrew scholars?
A Caesar
B Vigenere
C Scytale
D Atbash
D
Shifting each letter in the alphabet a fixed number of spaces to the right or left is an example of
what?
A Bit shifting
B Confusion
C Multi substitution
D Single substitution
D
Which of the following most accurately defines encryption?
A changing a message so it can only be easily read by the intended recipient
B Making binary changes to a message to conceal it
C changing a message using complex mathematics
D Applying keys to plain text
A
4|Page
EXAM (TESTING REAL EXAM QUESTIONS) AND VERIFIED
ANSWERS (MULTIPLE CHOICES) |COMPLETE SOLUTIONS
|A+ GRADED |100% CORRECT!!
What type of encryption uses different keys to encrypt and decrypt the message?
A Symmetric
B Private key
C Secure
D Asymmetric
D
The most widely used asymmetric encryption algorithm is what?
A RSA
B Vigenere
C DES
D Caesar Cipher
A
Original, unencrypted information is referred to as ____.
A text
B plaintext
C cleantext
D ciphertext
B
Which of the following is NOT an asymmetric system?
A PGP
B RSA
C SSL
D DES
D
1|Page
,In order for User A to send User B an encrypted message that only User B can read, User A must
encrypt message with which of the following keys?
A User A's public key
B User A's private key
C User B's public key
D User B's private key
C
The greatest weakness with symmetric algorithms is _____.
A They are less secure than asymmetric
B The problem of key exchange
C They are slower than asymmetric
D The problem of generating keys
B
Which of the following is generally true about block sizes?
A Smaller block sizes increase security
B Block sizes must be more than 256 bits to be secure
C Block size is irrelevant to security
D Larger block sizes increase security
D
A _____ is a function that takes a variable-size input m and returns a fixed-size string.
A Symmetric cipher
B Hash
C Asymmetric cipher
D Feistel
B
Which of the following is a cryptographic protocol that allows two parties to establish a shared
key over an insecure channel?
A Elliptic Curve
B RSA
2|Page
,C MD5
D Diffie-Hellman
D
A _________ is a digital representation of information that identifies you as a relevant entity by
a trusted third party?
A Digital Signature
B Hash
C Ownership stamp
D Digest
A
What is the standard used by most digital certificates?
A X.509
B CRL
C RFC 2298
D OCSP
A
DES uses keys of what size?
A 56 bits
B 192 bits
C 128 bits
D 64 bits
A
Which of the following is NOT a key size used by AES?
A 512 bits
B 128 bits
C 192 bits
D 256 bits
A
3|Page
, Which of the following was a multi alphabet cipher widely used from the 16th century (1553) to
the early 20th century (1900s)?
A Vigenere
B Caesar
C Atbash
D Scytale
A
Which of the following is a substitution cipher used by ancient Hebrew scholars?
A Caesar
B Vigenere
C Scytale
D Atbash
D
Shifting each letter in the alphabet a fixed number of spaces to the right or left is an example of
what?
A Bit shifting
B Confusion
C Multi substitution
D Single substitution
D
Which of the following most accurately defines encryption?
A changing a message so it can only be easily read by the intended recipient
B Making binary changes to a message to conceal it
C changing a message using complex mathematics
D Applying keys to plain text
A
4|Page
