Introduction to Cryptography Questions
and Answers 100% Pass
A business wants to use keys issued by a trusted third party to demonstrate to potential customers
that it is a legitimate organization. Which key is used t
...
Introduction to Cryptography Questions
and Answers 100% Pass
A business wants to use keys issued by a trusted third party to demonstrate to potential customers
that it is a legitimate organization. Which key is used to sign the certificate issued to the
business? ✔✔Private key of the root CA
A business wants to use keys issued by a trusted third party to demonstrate it is a legitimate
organization to potential customers. Which key should the business send to potential customers
to prove its identity? ✔✔Public key of the company
What should an administrator use to import and export all items written using X.509 that are part
of a chain of trust? ✔✔Public Key Cryptography Standard (PKCS) #12
Which field displays the hash, or digest, of the certificate in an X.509 certificate?
✔✔Thumbprint
Which certificate management process involves key recovery? ✔✔Issued
Which task does a root CA perform before publishing its own certificate? ✔✔Signing it with its
private key
Which algorithm is used to generate the thumbprint of a certificate? ✔✔SHA-1
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
What is the role of a key in asymmetric encryption and decryption? ✔✔A public key is used for
encryption, and a private key is used for decryption.
A security analyst is validating the integrity and authenticity of a data transaction. Which PKI
component is being used? ✔✔Digital signature
Which PKI component generates digital certificates? ✔✔Certificate authority (CA)
What is the maximum length (in bits) of encryption keys used by the WEP protocol? ✔✔40
What is a difference between WPA-Enterprise and WPA-Personal? ✔✔Support for an
authentication server
Which cipher is used with WEP? ✔✔RC4
How does TKIP improve WPA over WEP? ✔✔Hashes the initialization vector and secret key
An administrator has configured a virtual private network (VPN) connection utilizing IPsec
tunnel mode with Encapsulating Security Payload (ESP) between the corporate office and a
remote office. Where can the packets be inspected by intrusion detection systems (IDSs) and
virus scanners? ✔✔At the headquarters and the offsite location
Which default port must be open for the IPsec key exchange to be successful? ✔✔UDP 500
Which protocol indicates the virtual private network (VPN) is using Authentication Header
(AH)? ✔✔51
Which cipher uses a grid to map letters into numeric values? ✔✔Bifid
Which cipher uses a five-by-five matrix with nonrepeating characters? ✔✔Playfair
What does a frequency analysis attack to break encryption involve? ✔✔Analyzing ciphertext to
identify text variation and comparing the text to standard English characters
Which technique should a security analyst use to determine the key length in a Vigenère cipher?
✔✔Frequency analysis
What defines a prime number? ✔✔Only has factors of itself and 1
What is 29 mod 12? (Mod means remainder) ✔✔5
Which type of cipher is ChaCha? ✔✔Stream
What is the key size for RC4 with WEP? ✔✔40 bits
Which symmetric encryption technique uses a 56-bit key size and a 64-bit block size? ✔✔DES
Which wireless security standard uses a 128-bit RC4 stream cipher for encrypted
communications? ✔✔WPA
Employee B sends Employee A an encrypted message. What does Employee A use to decrypt
the message from Employee B? ✔✔Employee A's private key
What is an example of a symmetric algorithm? ✔✔AES
Which two components involved in performing encryption are known to the party that will
perform decryption before symmetric encryption is applied? Choose 2 answers.
✔✔Cryptographic key
Initialization vector
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
What happens to the hash of a file if it is rehashed after the first character of the file is changed?
✔✔The entire hash is different.
What is the length (in bits) of an MD5 hash output? ✔✔128
How many characters are used in an LM hash password? ✔✔14
A Windows credential is identified as follows:
user:FDA95FBABC199D22LLD3B435B51876KK:199DDFD4EF0E9CD9KMNC6FE771IL124
B8::: What is used to store this password? ✔✔NTLM
What is a rainbow table? ✔✔Precompiled list of hash values
Which mode encrypts each group with the same key, leaving each group independent of the
others? ✔✔ECB (Electronic Code Book)
Which mode of block encryption results in the same outcome for matching blocks of a plaintext
message? ✔✔Electronic Code Book (ECB)
How does CBC mode encryption function? ✔✔Uses an initialization vector (IV) to encrypt the
first block, then uses the result of the encryption to encrypt the next block
Which encryption mode always produces the same result for the same plaintext? ✔✔ECB
Electronic Code Book
Which information protection method has an 80-bit key and operates on 64-bit data blocks?
✔✔Skipjack
How many transformation rounds does AES use with a 192-bit key? ✔✔12
How many transformation rounds does AES use with a 128-bit key? ✔✔10
Which encryption algorithm did the National Institute of Standards and Technology (NIST)
designate as a specification for the encryption of electronic information? ✔✔AES
Which attack tries every combination of letters, numbers, and special characters? ✔✔Brute-force
How does a dictionary attack break a cipher? ✔✔Takes a list of the most common words and
tries each entry
A security analyst decrypted a data set with the same key that originally encrypted the data set.
Which cryptographic operation did the analyst use? ✔✔Symmetric
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? ✔✔Symmetric block
Why is symmetric stream used to encrypt video when speed is a major concern? ✔✔It uses the
same key to encrypt and decrypt large amounts of media.
Why should an asymmetric public key be used to encrypt a symmetric key that is being sent to
one person? ✔✔It encrypts a small amount of information, which is decrypted with the
corresponding private key.
Which type of attacks are Diffie-Hellman methods vulnerable to? ✔✔Man-in-the-middle
Which mechanism mitigates a copy-and-paste attack when using AES? ✔✔Output feedback
(OFB) loop
Which mechanism can be used to ensure perfect forward secrecy during key exchange when
using symmetric encryption? ✔✔ECDH (Elliptic-curve Diffie-Hellman)
Which encryption component ensures that the compromise of a long-term key prevents the
compromise of any previous session keys? ✔✔Forward secrecy
What can XOR use as a pseudorandom number to create unique ciphertext? ✔✔Initialization
vector
How does cipher block chaining (CBC) create randomness in a second block after encrypting the
first block with an initialization vector (IV)? ✔✔Uses the results of the IV to encrypt the next
block
How is information about Bitcoin transactions stored? ✔✔Distributed peer-to-peer network
What is one of the primary characteristics of a blockchain in the context of Bitcoin? ✔✔Adding
blocks to a blockchain is computationally expensive.
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? ✔✔256
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