Which one of the following is true for asymmetric-key cryptography ?
2014
Which one of the following is true for asymmetric-key cryptography ?
- A.
Private key is kept by the receiver and public key is announced to the public.
- B.
Public key is kept by the receiver and private key is announced to the public.
- C.
Both private key and public key are kept by the receiver.
- D.
Both private key and public key are announced to the public.
Attempted by 235 students.
Show answer & explanation
Correct answer: A
Key idea: In asymmetric cryptography each participant has a pair of keys: a public key that is shared and a private key that is kept secret.
Confidentiality example: A sender encrypts a message using the recipient's public key; only the recipient can decrypt it with their private key.
Authentication (digital signature) example: A signer creates a signature with their private key; anyone can verify the signature using the signer's public key.
Security requirement: The private key must remain secret; publishing the private key eliminates security guarantees.
Therefore, the correct description is: "Private key is kept by the receiver and public key is announced to the public."
Short tip: To send confidential data to someone, encrypt with their public key; to verify who signed a message, check the signature with the signer’s public key.