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NSE4 · Question #58

Bob wants to send Alice a file that is encrypted using public key cryptography. Which of the following statements is correct regarding the use of public key cryptography in this scenario?

The correct answer is C. Bob will use Alice's public key to encrypt the file and Alice will use her private key to decrypt the. For secure file transmission using public key cryptography, Bob encrypts the file with Alice's public key, ensuring that only Alice, who possesses the corresponding private key, can decrypt it.

Submitted by hans_de· Apr 18, 2026VPN and ZTNA

Question

Bob wants to send Alice a file that is encrypted using public key cryptography. Which of the following statements is correct regarding the use of public key cryptography in this scenario?

Options

  • ABob will use his private key to encrypt the file and Alice will use her private key to decrypt the file.
  • BBob will use his public key to encrypt the file and Alice will use Bob's private key to decrypt the
  • CBob will use Alice's public key to encrypt the file and Alice will use her private key to decrypt the
  • DBob will use his public key to encrypt the file and Alice will use her private key to decrypt the file.

How the community answered

(37 responses)
  • A
    5% (2)
  • B
    3% (1)
  • C
    89% (33)
  • D
    3% (1)

Why each option

For secure file transmission using public key cryptography, Bob encrypts the file with Alice's public key, ensuring that only Alice, who possesses the corresponding private key, can decrypt it.

ABob will use his private key to encrypt the file and Alice will use her private key to decrypt the file.

Using Bob's private key for encryption is for digital signing (authenticity/non-repudiation), not confidentiality, and Alice's private key would not decrypt it.

BBob will use his public key to encrypt the file and Alice will use Bob's private key to decrypt the

Bob's public key is publicly available and would not provide confidentiality for a message sent to Alice, and Alice would not possess Bob's private key to decrypt it.

CBob will use Alice's public key to encrypt the file and Alice will use her private key to decrypt theCorrect

In public key cryptography for confidentiality, the sender (Bob) uses the recipient's (Alice's) public key to encrypt the data. This encrypted data can then only be decrypted by the corresponding private key, which only Alice possesses.

DBob will use his public key to encrypt the file and Alice will use her private key to decrypt the file.

Bob's public key is for others to encrypt messages *to* Bob, or for Bob to verify signatures, not for Bob to encrypt a confidential message *for* Alice.

Concept tested: Public key cryptography for confidentiality

Source: https://docs.microsoft.com/en-us/windows/win32/seccrypto/public-key-cryptography

Topics

#Public Key Cryptography#Encryption#Decryption#Asymmetric Encryption

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