nerdexam
CompTIA

SK0-004 · Question #767

A technician wants to send a secure message to a user. The technician receives the public encryption keys from the user. Which of the following actions would be a prudent response?

The correct answer is B. Send the user an encrypted message. Receiving a user's public key is the standard first step in asymmetric encryption; the correct action is to use that key to encrypt a message only the user can decrypt.

Security and disaster recovery

Question

A technician wants to send a secure message to a user. The technician receives the public encryption keys from the user. Which of the following actions would be a prudent response?

Options

  • ANotify the security team
  • BSend the user an encrypted message
  • CRevoke the compromised keys
  • DAdd the encryption keys to the CRL

How the community answered

(54 responses)
  • A
    2% (1)
  • B
    91% (49)
  • C
    6% (3)
  • D
    2% (1)

Why each option

Receiving a user's public key is the standard first step in asymmetric encryption; the correct action is to use that key to encrypt a message only the user can decrypt.

ANotify the security team

Receiving a public key is a routine operation in PKI and does not constitute a security incident requiring team notification.

BSend the user an encrypted messageCorrect

In asymmetric (public-key) cryptography, a sender encrypts a message using the recipient's public key. Only the recipient's paired private key can decrypt it, ensuring confidentiality. Receiving a public key is a normal, expected part of this workflow and requires no alarm.

CRevoke the compromised keys

Revoking keys is appropriate only when a private key is compromised or a certificate is no longer trusted, not when legitimately receiving a public key.

DAdd the encryption keys to the CRL

A Certificate Revocation List (CRL) is used to publish invalidated certificates, not to store or register public keys received from other users.

Concept tested: Asymmetric encryption public key usage

Source: https://csrc.nist.gov/publications/detail/sp/800-57-part-1/rev-5/final

Topics

#public key encryption#PKI#secure messaging

Community Discussion

No community discussion yet for this question.

Full SK0-004 Practice