C839 Introduction to Cryptography Exam Questions with Correct Answers| Latest Update
Guaranteed Success
Pigpen Cipher a geometric simple substitution cipher, which exchanges letters for symbols
which are fragments of a grid
Rail Code Employs a method to scramble text by writing it in a sequence across a number of
rails.
BIFID Makes use of a grid and which maps the letters into numeric values.
Playfair Cipher Invented by Charles Wheatstone in 1854. Encrypts two letters instead of one,
this makes it more complex. Uses a 5x5 table containing a keyword. No more secure than any
other older ciphers.
Caesar Mono
alphabetic substitution cipher known as "shift" cipher. Involves plaintext being replaced by a
letter some fixed number of
positions down the alphabet. i.e., a Caesar Cipher using a shift of +3 would mean a plaintext
letter A would result in a ciph ert ext letter
D (a shift of three positions to the right in the alphabet).
Vigenere Cipher Polyalphabetic cipher that involves using a different mapping, based on a
keyword, for each character of the cipher. An advantage of this type of cipher is that the same
plaintext character is likely to be coded to different mappings, depending on the position of the
keyword, making guessing more difficult.
one-time pad (OTP) Cipher code mapping that is used only once. Advantage is it is
essentially unbreakable; disadvantage is it takes lots of work
as you'd have to generate the pad to be used, each time.
,Four-square Uses four 5
× 5 matrices arranged in a square, are where each matrix contains 25 letters for encoding and
decoding operations.
Enigma Machine Used a polyalphabetic substitution cipher, which did not repeat within a
reasonable time period, along with a secret key. For the cracking of the Enigma cipher, the
challenge was thus to determine both the algorithm used and the key. Enigma's main weakness
though, was that none of the plain text letters could be ciphered as itself.
ECB (Electronic Code Book) Cipher mode A key encrypts each block -- the cipher
CFB (Cipher Feedback Mode) IV encrypted by a key XORed with the block producing the
cipher. Which is passed on to the next link to be encrypted by a key which in turn is XORed with
the next block and produces a cipher. Block to stream
OFB (Output Feedback Mode) Key encrypts the IV. The encryption is sent to the next block
before the current block is XORed with the encryption creating the cipher. Block to stream,
Counter Mode (CTR) Nonce with counter is encrypted by the key XORed with the block
creating a cipher. no chaining similar to ECM. Block to stream.
public cryptography standard (PKCS) #12 What should an administrator use to import and
export all items written using X.509 that are part of a chain of trust?
ECB Which encryption mode always produces the same result for the same plain text?
Symmetric block What should be used when large amounts of data need to be encrypted
and decrypted for secure storage based on groupings of 128, 192, or 256 bits?
,Public Key Cryptography Standard (PKCS) #12 What should an administrator use to import
and export all items written using X.509 that are part of a chain of trust?
Employee B's public key Employee A created a secret key and wants to send it to Employee
B without any coworkers being able to decrypt the message.
Which key needs to encrypt the message?
WPA Which wireless security standard uses a 128-bit RC4 stream cipher for encrypted
communications?
Uses an initialization vector (IV) to encrypt the first block, then uses the result of the encryption
to encrypt the next block How does CBC mode encryption function?
Symmetric block What should be used when large amounts of data need to be encrypted
and decrypted for secure storage based on groupings of 128, 192, or 256 bits?
256 What is the length (in bits) of the private key used to sign transactions and associated
with an individual wallet in the context of Bitcoin?
Issued Which certificate management process involves key recovery?
Large volumes of plaintext need to be encrypted, and the encryption keys need to be securely
distributed.
Which approach should be used for encryption and distribution? Encrypt by using symmetric
keys and distribute by using asymmetric keys
, Digital signature A security analyst is validating the integrity and authenticity of a data
transaction.
Which PKI component is being used?
Playfair Which cipher uses a five-by-five matrix with nonrepeating characters?
Cryptography the science that studies encryption, which is the hiding of messages so that
only the sender and receiver can read them. Cybersecurity, computer science, programming,
and other IT career fields require a conceptual understanding of cryptography and familiarity
with its basic vocabulary.
Caesar Cypher letter-by-letter method to make a cipher. For each letter, substitute another
letter 4 letters ahead. For "a", write "d".
Employee B sends Employee A an encrypted message. What does employee A use to decrypt
the message from employee B Employee As private key
Advanced encryption system (AES) is an example of a symmetric algorithm. RSA, SHA, and
MD5 are not symmetric algorithms.
Employee A created a secret key and wants to send it to Employee B without any coworkers
being able to decrypt the message. Which key needs to encrypt the message? Employee B's
public key
Which type of cipher is ChaCha? stream
Guaranteed Success
Pigpen Cipher a geometric simple substitution cipher, which exchanges letters for symbols
which are fragments of a grid
Rail Code Employs a method to scramble text by writing it in a sequence across a number of
rails.
BIFID Makes use of a grid and which maps the letters into numeric values.
Playfair Cipher Invented by Charles Wheatstone in 1854. Encrypts two letters instead of one,
this makes it more complex. Uses a 5x5 table containing a keyword. No more secure than any
other older ciphers.
Caesar Mono
alphabetic substitution cipher known as "shift" cipher. Involves plaintext being replaced by a
letter some fixed number of
positions down the alphabet. i.e., a Caesar Cipher using a shift of +3 would mean a plaintext
letter A would result in a ciph ert ext letter
D (a shift of three positions to the right in the alphabet).
Vigenere Cipher Polyalphabetic cipher that involves using a different mapping, based on a
keyword, for each character of the cipher. An advantage of this type of cipher is that the same
plaintext character is likely to be coded to different mappings, depending on the position of the
keyword, making guessing more difficult.
one-time pad (OTP) Cipher code mapping that is used only once. Advantage is it is
essentially unbreakable; disadvantage is it takes lots of work
as you'd have to generate the pad to be used, each time.
,Four-square Uses four 5
× 5 matrices arranged in a square, are where each matrix contains 25 letters for encoding and
decoding operations.
Enigma Machine Used a polyalphabetic substitution cipher, which did not repeat within a
reasonable time period, along with a secret key. For the cracking of the Enigma cipher, the
challenge was thus to determine both the algorithm used and the key. Enigma's main weakness
though, was that none of the plain text letters could be ciphered as itself.
ECB (Electronic Code Book) Cipher mode A key encrypts each block -- the cipher
CFB (Cipher Feedback Mode) IV encrypted by a key XORed with the block producing the
cipher. Which is passed on to the next link to be encrypted by a key which in turn is XORed with
the next block and produces a cipher. Block to stream
OFB (Output Feedback Mode) Key encrypts the IV. The encryption is sent to the next block
before the current block is XORed with the encryption creating the cipher. Block to stream,
Counter Mode (CTR) Nonce with counter is encrypted by the key XORed with the block
creating a cipher. no chaining similar to ECM. Block to stream.
public cryptography standard (PKCS) #12 What should an administrator use to import and
export all items written using X.509 that are part of a chain of trust?
ECB Which encryption mode always produces the same result for the same plain text?
Symmetric block What should be used when large amounts of data need to be encrypted
and decrypted for secure storage based on groupings of 128, 192, or 256 bits?
,Public Key Cryptography Standard (PKCS) #12 What should an administrator use to import
and export all items written using X.509 that are part of a chain of trust?
Employee B's public key Employee A created a secret key and wants to send it to Employee
B without any coworkers being able to decrypt the message.
Which key needs to encrypt the message?
WPA Which wireless security standard uses a 128-bit RC4 stream cipher for encrypted
communications?
Uses an initialization vector (IV) to encrypt the first block, then uses the result of the encryption
to encrypt the next block How does CBC mode encryption function?
Symmetric block What should be used when large amounts of data need to be encrypted
and decrypted for secure storage based on groupings of 128, 192, or 256 bits?
256 What is the length (in bits) of the private key used to sign transactions and associated
with an individual wallet in the context of Bitcoin?
Issued Which certificate management process involves key recovery?
Large volumes of plaintext need to be encrypted, and the encryption keys need to be securely
distributed.
Which approach should be used for encryption and distribution? Encrypt by using symmetric
keys and distribute by using asymmetric keys
, Digital signature A security analyst is validating the integrity and authenticity of a data
transaction.
Which PKI component is being used?
Playfair Which cipher uses a five-by-five matrix with nonrepeating characters?
Cryptography the science that studies encryption, which is the hiding of messages so that
only the sender and receiver can read them. Cybersecurity, computer science, programming,
and other IT career fields require a conceptual understanding of cryptography and familiarity
with its basic vocabulary.
Caesar Cypher letter-by-letter method to make a cipher. For each letter, substitute another
letter 4 letters ahead. For "a", write "d".
Employee B sends Employee A an encrypted message. What does employee A use to decrypt
the message from employee B Employee As private key
Advanced encryption system (AES) is an example of a symmetric algorithm. RSA, SHA, and
MD5 are not symmetric algorithms.
Employee A created a secret key and wants to send it to Employee B without any coworkers
being able to decrypt the message. Which key needs to encrypt the message? Employee B's
public key
Which type of cipher is ChaCha? stream
