CompTIA CompTIA Security+ JK0-022 Questions & Answers

• Question 701:

  Ann wants to send a file to Joe using PKI. Which of the following should Ann use in order to sign the file?

  A. Joe's public key

  B. Joe's private key

  C. Ann's public key

  D. Ann's private key

  Correct Answer: D

  The sender uses his private key, in this case Ann's private key, to create a digital signature. The message is, in effect, signed with the private key. The sender then sends the message to the receiver. The receiver uses the public key attached to the message to validate the digital signature. If the values match, the receiver knows the message is authentic. The receiver uses a key provided by the sender--the public key--to decrypt the message. Most digital signature implementations also use a hash to verify that the message has not been altered, intentionally or accidently, in transit.

  Incorrect Answers:

  A: The sender's (Ann's) not Joe's key must be used.

  B: The sender's (Ann's) not Joe's key must be used.

  C: The sender's private key, not her public key, is used to sign the message file.

  References:

  Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, pp 279-285

• Question 702:

  Which of the following explains the difference between a public key and a private key?

  A. The public key is only used by the client while the private key is available to all. Both keys are mathematically related.

  B. The private key only decrypts the data while the public key only encrypts the data. Both keys are mathematically related.

  C. The private key is commonly used in symmetric key decryption while the public key is used in asymmetric key decryption.

  D. The private key is only used by the client and kept secret while the public key is available to all.

  Correct Answer: D

  The private key must be kept secret at all time. The private key is only by the client. The public key is available to anybody.

  Incorrect Answers:

  A: The private key is only by the client, while the public key is used by all.

  B: You can use the private key to encrypt data. Then you would need to use the public key to decrypt it.

  C: The key pair, consisting of a private key and a public key, is used in asymmetric encryption and asymmetric decryption.

  References:

  Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, pp 279-285

• Question 703:

  Public keys are used for which of the following?

  A. Decrypting wireless messages

  B. Decrypting the hash of an electronic signature

  C. Bulk encryption of IP based email traffic

  D. Encrypting web browser traffic

  Correct Answer: B

  The sender uses the private key to create a digital signature. The message is, in effect, signed with the private key. The sender then sends the message to the receiver. The receiver uses the public key attached to the message to validate the digital signature. If the values match, the receiver knows the message is authentic.

  Incorrect Answers:

  A: Wireless traffic is not decrypted by public keys.

  C: Public keys are not used to encrypt email traffic.

  D: Public keys are not used to encrypt web browser traffic.

  References:

  Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, pp 279-285

• Question 704:

  The public key is used to perform which of the following? (Select THREE).

  A. Validate the CRL

  B. Validate the identity of an email sender

  C. Encrypt messages

  D. Perform key recovery

  E. Decrypt messages

  F. Perform key escrow

  Correct Answer: BCE

  B: The sender uses the private key to create a digital signature. The message is, in effect, signed with the private key. The sender then sends the message to the receiver. The receiver uses the public key attached to the message to validate the digital signature. If the values match, the receiver knows the message is authentic.

  C: The sender uses the public key to encrypt a message, and the receiver uses the private key to decrypt the message.

  E: You encrypt data with the private key and decrypt with the public key, though the opposite is much more frequent. Public-key cryptography, also known as asymmetric cryptography, is a class of cryptographic protocols based on algorithms that require two separate keys, one of which is secret (or private) and one of which is public. Although different, the two parts of this key pair are mathematically linked.

  Incorrect Answers:

  A: The CRL does not need to be validated.

  A CRL is a locally stored record containing revoked certificates and revoked keys.

  D: Key recovery is done through the key recovery agent. The key recovery agent does not use the public key.

  F: The key escrow process does not use the public key.

  References:

  Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, pp 262, 279-285, 285

• Question 705:

  The security administrator installed a newly generated SSL certificate onto the company web server. Due to a misconfiguration of the website, a downloadable file containing one of the pieces of the key was available to the public. It was verified that the disclosure did not require a reissue of the certificate. Which of the following was MOST likely compromised?

  A. The file containing the recovery agent's keys.

  B. The file containing the public key.

  C. The file containing the private key.

  D. The file containing the server's encrypted passwords.

  Correct Answer: B

  The public key can be made available to everyone. There is no need to reissue the certificate.

  Incorrect Answers:

  A: The recovery agent has no key.

  C: The private key must be secret. If the private key is made available to a third party, then the key must be revoked.

  D: Encrypted passwords would not be a security risk. It would be hard to decrypt them.

  References:

  Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, pp 279-285

• Question 706:

  Which of the following is synonymous with a server's certificate?

  A. Public key

  B. CRL

  C. Private key

  D. Recovery agent

  Correct Answer: A

  A public key certificate (also known as a digital certificate or identity certificate) is an electronic document used to prove ownership of a public key.

  Incorrect Answers:

  B: A CRL is not a certificate. It is a database consisting of revoked keys and signatures.

  C: A private key is not a certificate. A public key is a certificate.

  D: A recovery agent is not a certificate. A recovery agent is used to recover keys.

  References:

  Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, pp 262, 279-285, 285

• Question 707:

  The recovery agent is used to recover the:

  A. Root certificate

  B. Key in escrow

  C. Public key

  D. Private key

  Correct Answer: D

  A key recovery agent is an entity that has the ability to recover a private key, key components, or plaintext messages as needed. Using the recovered key the recovery agent can decrypt encrypted data.

  Incorrect Answers:

  A: The key recovery agent recovers the private key, not the root certificate.

  B: The key recovery agent recovers the private key, not key in escrow.

  C: The key recovery agent recovers the private key, not the public key.

  References:

  Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, pp 279-285

• Question 708:

  Which of the following is true about the recovery agent?

  A. It can decrypt messages of users who lost their private key.

  B. It can recover both the private and public key of federated users.

  C. It can recover and provide users with their lost or private key.

  D. It can recover and provide users with their lost public key.

  Correct Answer: A

  A key recovery agent is an entity that has the ability to recover a private key, key components, or plaintext messages as needed. Using the recovered key the recovery agent can decrypt encrypted data.

  Incorrect Answers:

  B: The key recovery agent does not recover the public key. The key recovery agent recovers the private key which then is used to decrypt the data.

  C: The key recovery agent does indeed recovery the private key.

  D: The key recovery agent does not recover the public key.

  References:

  Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, pp 279-285

• Question 709:

  After encrypting all laptop hard drives, an executive officer's laptop has trouble booting to the operating system. Now that it is successfully encrypted the helpdesk cannot retrieve the data.

  Which of the following can be used to decrypt the information for retrieval?

  A. Recovery agent

  B. Private key

  C. Trust models

  D. Public key

  Correct Answer: A

  To access the data the hard drive need to be decrypted. To decrypt the hard drive you would need the proper private key. The key recovery agent can retrieve the required key. A key recovery agent is an entity that has the ability to recover a key, key components, or plaintext messages as needed.

  Incorrect Answers:

  B: The private key is not readily accessible. You would have to

  C: A trust Model is collection of rules that informs application on how to decide the legitimacy of a Digital Certificate. A trust model cannot recover keys.

  D: The public key cannot be used to decrypt the hard drive.

  References:

  Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, pp 262, 279-285, 285-289

• Question 710:

  Pete, an employee, is terminated from the company and the legal department needs documents from his encrypted hard drive. Which of the following should be used to accomplish this task? (Select TWO).

  A. Private hash

  B. Recovery agent

  C. Public key

  D. Key escrow

  E. CRL

  Correct Answer: BD

  B: If an employee leaves and we need access to data he has encrypted, we can use the key recovery agent to retrieve his decryption key. We can use this recovered key to access the data. A key recovery agent is an entity that has the ability to recover a key, key components, or plaintext messages as needed. As opposed to escrow, recovery agents are typically used to access information that is encrypted with older keys.

  D: If a key need to be recovered for legal purposes the key escrow can be used. Key escrow addresses the possibility that a third party may need to access keys. Under the conditions of key escrow, the keys needed to encrypt/decrypt data are held in an escrow account (think of the term as it relates to home mortgages) and made available if that third party requests them. The third party in question is generally the government, but it could also be an employer if an employee's private messages have been called into question.

  Incorrect Answers:

  A: Private hash is not used within the PKI framework.

  C: A public key is publically known and would not have to be retrieved.

  E: A CRL is a locally stored record containing revoked certificates and revoked keys. A CRL cannot be used to recover lost keys.

  References:

  Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, pp 262, 279-285, 285