Pre-assesment - Introduction to Cryptography - C839 - WGU

1. 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

Public key of the root CA

Private key of the company

Public key of the company

Private key of the root CA

2. 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?

Private key of the root CA

Public key of the root CA

Private key of the company

Public key of the company

Public key of the company

3. What should an administrator use to import and export all items written using X.509 that are part of a chain of trust?

CER

Public Key Cryptography Standard (PKCS) #7

Public Key Cryptography Standard (PKCS) #12

RTF

Public Key Cryptography Standard (PKCS) #12

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

Subject

Issuer

Version

Thumbprint

Thumbprint

5. 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 B's private key

Employee A's public key

Employee B's public key

Employee A's private key

6. What is an example of a symmetric algorithm?

RSA

AES

SHA

MD5

AES

7. 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

Plaintext content

Initialization vector

Nonce value

Cryptographic algorithm

Cryptographic key

8. 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 A's public key

Employee A's private key

Employee B's public key

Employee B's private key

Employee B's public key

9. Which type of cipher is ChaCha?

Asymmetric

Block

Stream

Hash

Stream

10. What is the key size for RC4 with WEP?

40 bits

128 bits

256 bits

512 bits

40 bits

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

AES

DES

3DES

IDEA

DES

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

WPA

WEP

VPN

GSM

WPA

13. What defines a prime number?

Only has factors of itself and 1

Only has factors of itself and 2

Evenly divisible by 3.14

Evenly divisible by 10

Only has factors of itself and 1

14. What is 29 mod 12?

0

3

5

7

5

15. 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.

The beginning of the hash is altered.

The hash is unaltered.

The hash algorithm is replaced.

The entire hash is different.

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

32

64

128

256

128

17. How many characters are used in an LM hash password?

7

8

14

16

14

18. A Windows credential is identified as follows: user:FDA95FBABC199D22LLD3B435B51876KK:199DDFD4EF0E9CD9KMNC6FE771IL124B8:::

What is used to store this password?

MD5

Bcrypt

SHA-512

NTLM

NTLM

19. What is a rainbow table?

List of matching usernames and passwords

Precompiled list of common words

List of commonly used passwords

Precompiled list of hash values

Precompiled list of common words

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

ECB

CBC

CFB

OFB

ECB

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

Electronic Code Book (ECB)

Output feedback (OFB)

Cipher block chaining (CBC)

Cipher feedback (CFB)

ECB

22. How does CBC mode encryption function?

Encrypts each block with the same key, where each block is independent of the others

Uses an initialization vector (IV) to encrypt the first block, then uses the result of the encryption to encrypt the next block

Uses a self-synchronizing stream on the blocks, where the initialization vector (IV) is encrypted and XORed with the data stream

Converts from block into stream, then uses a counter value and a nonce to encrypt the data

Uses an initialization vector (IV) to encrypt the first block, then uses the result of the encryption to encrypt the next block

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

CBC

ECB

CFB

CTR

ECB

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

Skipjack

IDEA

DES

Twofish

Skipjack

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

10

12

14

16

12

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

10

12

14

16

10

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

IDEA

DES

3DES

AES

AES

28. A security analyst decrypted a data set with the same key that originally encrypted the data set.

Which cryptographic operation did the analyst use?

Asymmetric

Symmetric

Hashing

Kerberos

Symmetric

29. 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 stream

Symmetric block

Asymmetric public key

Asymmetric private key

Symmetric block

30. Why is symmetric stream used to encrypt video when speed is a major concern?

It signs files and encrypts that hash of the file to verify integrity and authenticity.

It encrypts and decrypts data in blocks of characters at a time with a complex algorithm.

It encrypts a small amount of information, which is decrypted with a private key.

It uses the same key to encrypt and decrypt large amounts of media.

It uses the same key to encrypt and decrypt large amounts of media.

31. Why should an asymmetric public key be used to encrypt a symmetric key that is being sent to one person?

It uses the same key to encrypt and decrypt large amounts of media, one bit at a time.

It encrypts and decrypts data in blocks of characters at a time with a complex algorithm.

It encrypts a small amount of information, which is decrypted with the corresponding private key.

It signs files and encrypts the hash of the file to verify integrity and authenticity.

It encrypts a small amount of information, which is decrypted with the corresponding private key.

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

Man-in-the-middle

Brute-force

Rainbow

Dictionary

Man-in-the-middle

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

Electronic Code Book (ECB)

Output feedback (OFB) loop

Message digest 6 (MD6)

Secure Hash Algorithm 1 (SHA-1)

Output feedback (OFB) loop

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

MD5

ECDSA

ECDH

SHA-2

ECDH

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

Integrity check

Client hello

Server hello

Forward secrecy

Forward secrecy

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

Symmetric key

Message digest

Permanent password

Initialization vector

Initialization vector

37. 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

Increments the IV to encrypt the next block

Creates a new, random IV to encrypt the next block

Generates a new IV to encrypt the next block

Uses the results of the IV to encrypt the next block

38. How is information about Bitcoin transactions stored?

Command and control center

Platform as a service in the cloud

Infrastructure as a service in the cloud

Distributed peer-to-peer network

Distributed peer-to-peer network

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

Adding blocks to a blockchain is computationally expensive.

The security of the chain in a blockchain is independent of its length.

Transactions between each block are chained.

Transactions within each block are chained.

Transactions between each block are chained.

40. 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?

64

128

256

512

256

41. Which certificate management process involves key recovery?

Initialization

Issued

Cancellation

Hold

Issued

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

Encrypting it with its private key

Encrypting it with its public key

Signing it with its private key

Signing it with its public key

Signing it with its private key

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

RSA

3DES

AES

SHA-1

SHA-1

44. 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

Encrypt by using asymmetric keys and distribute by using symmetric keys

Encrypt by using symmetric keys and distribute by using symmetric keys

Encrypt by using asymmetric keys and distribute by using asymmetric keys

Encrypt by using symmetric keys and distribute by using asymmetric keys

45. What is the role of a key in asymmetric encryption and decryption?

A public key is used for both encryption and decryption.

A private key is used for both encryption and decryption.

A public key is used for encryption, and a private key is used for decryption.

A private key is used for encryption, and a public key is used for decryption.

A public key is used for encryption, and a private key is used for decryption.

46. A security analyst is validating the integrity and authenticity of a data transaction.

Which PKI component is being used?

Digital certificate

Digital signature

Asymmetric encryption

Symmetric encryption

Digital signature

47. Which PKI component generates digital certificates?

Certificate signing request (CSR)

Certificate policy (CP)

Certificate revocation list (CRL)

Certificate authority (CA)

Certificate authority (CA)

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

40

56

128

256

40

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

Support for Temporal Key Integrity Protocol

Support for an authentication server

Use of a session key

Use of a 48-bit initialization vector

Support for an authentication server

50. Which cipher is used with WEP?

RC5

RC4

TKIP

AES

RC4

51. How does TKIP improve WPA over WEP?

Hashes the initialization vector and secret key

Implements a RADIUS server

Implements an authentication server

Creates an AES encryption key

Hashes the initialization vector and secret key

52. 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?

Only at the headquarters

Only at the offsite location

At the headquarters and the offsite location

Between the headquarters and the offsite location

At the headquarters and the offsite location

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

UDP 162

TCP 389

TCP 465

UDP 500

UDP 500

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

48

50

51

58

51

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

Bifid

SHA-1

Caesar

Vigenère

Bifid

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

Playfair

Rail code

Pigpen

Vigenère

Playfair

57. What does a frequency analysis attack to break encryption involve?

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

Performing an exhaustive search to attempt every possible mapping or key

Interfering between two parties and sometimes intercepting or modifying data in the communication stream

Identifying part of the ciphertext and the corresponding plaintext

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

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

Frequency analysis

Brute force

Kasiski examination

Known plaintext

Kasiski examination

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

Rainbow table

Birthday

Dictionary

Brute-force

Brute-force

60. How does a dictionary attack break a cipher?

Factors the prime numbers used within an RSA algorithm

Looks for rollover of the same value for an IV

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

Matches hash values back to the original plaintext

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

What will a Layer 2 switch do when the destination MAC address of a received frame is not in the MAC table?

It initiates an ARP request.

It broadcasts the frame out of all ports on the switch.

It notifies the sending host that the frame cannot be delivered.

It forwards the frame out of all ports except for the port at which the frame was received.

It forwards the frame out of all ports except for the port at which the frame was received.

What are two features of ARP? (Choose two.)

If a host is ready to send a packet to a local destination device and it has the IP address but not the MAC address of the destination, it generates an ARP broadcast.*

An ARP request is sent to all devices on the Ethernet LAN and contains the IP address of the destination host and its multicast MAC address.

When a host is encapsulating a packet into a frame, it refers to the MAC address table to determine the mapping of IP addresses to MAC addresses.

If no device responds to the ARP request, then the originating node will broadcast the data packet to all devices on the network segment.

If a device receiving an ARP request has the destination IPv4 address, it responds with an ARP reply.

If a host is ready to send a packet to a local destination device and it has the IP address but not the MAC address of the destination, it generates an ARP broadcast.

If a device receiving an ARP request has the destination IPv4 address, it responds with an ARP reply.