C839- Cryptography

How many transformation rounds does AES use with a 128-bit key?

10

How many transformation rounds does AES use with a 192-bit key?

12

What is the length (in bits) of an MD5 hash output?

128

How many characters are used in an LM hash password?

14

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

What is the maximum length (in bits) of encryption keys used by the WEP protocol?

40

What is the key size for RC4 with WEP?

40 bits

What is 29 mod 12?

5

Which protocol indicates the virtual private network (VPN) is using Authentication Header (AH)?

51

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.

What is an example of a symmetric algorithm?

AES

Which encryption algorithm did the National Institute of Standards and Technology (NIST) designate as a specification for the encryption of electronic information?

AES

What is one of the primary characteristics of a blockchain in the context of Bitcoin?

Adding blocks to a blockchain is computationally expensive.

What does a frequency analysis attack to break encryption involve?

Analyzing ciphertext to identify text variation and comparing the text to standard English characters

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 PKI component generates digital certificates?

Certificate authority (CA)

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 algorithm & Cryptographic key

Which symmetric encryption technique uses a 56-bit key size and a 64-bit block size?

DES

A security analyst is validating the integrity and authenticity of a data transaction.Which PKI component is being used?

Digital signature

How is information about Bitcoin transactions stored?

Distributed peer-to-peer network

Which encryption mode always produces the same result for the same plaintext?

ECB

Which mode encrypts each group with the same key, leaving each group independent of the others?

ECB

Which mechanism can be used to ensure perfect forward secrecy during key exchange when using symmetric encryption?

ECDH

Which mode of block encryption results in the same outcome for matching blocks of a plaintext message?

Electronic Code Book (ECB)

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

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

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

Which encryption component ensures that the compromise of a long-term key prevents the compromise of any previous session keys?

Forward secrecy

How does TKIP improve WPA over WEP?

Hashes the initialization vector and secret key

What can XOR use as a pseudorandom number to create unique ciphertext?

Initialization vector

Which certificate management process involves key recovery?

Issued

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.

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.

Which technique should a security analyst use to determine the key length in a Vigenère cipher?

Kasiski examination

Which type of attacks are Diffie-Hellman methods vulnerable to?

Man-in-the-middle

A Windows credential is identified as follows: user:FDA95FBABC199D22LLD3B435B51876KK:199DDFD4EF0E9CD9KMNC6FE771IL124B8:::What is used to store this password?

NTLM

What defines a prime number?

Only has factors of itself and 1

Which mechanism mitigates a copy-and-paste attack when using AES?

Output feedback (OFB) loop

What is a rainbow table?

Precompiled list of hash values

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

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

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

Which cipher is used with WEP?

RC4

Which algorithm is used to generate the thumbprint of a certificate?

SHA-1

Which task does a root CA perform before publishing its own certificate?

Signing it with its private key

Which information protection method has an 80-bit key and operates on 64-bit data blocks?

Skipjack

What is a difference between WPA-Enterprise and WPA-Personal?

Support for an authentication server

How does a dictionary attack break a cipher?

Takes a list of the most common words and tries each entry

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.

Which default port must be open for the IPsec key exchange to be successful?

UDP 500

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

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

Which wireless security standard uses a 128-bit RC4 stream cipher for encrypted communications?

WPA

Which cipher uses a grid to map letters into numeric values?

bifid

Which attack tries every combination of letters, numbers, and special characters?

brute force

Which cipher uses a five-by-five matrix with nonrepeating characters?

playfair

Which type of cipher is ChaCha?

stream

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

Which field displays the hash, or digest, of the certificate in an X.509 certificate?

thumbprint