In public key cryptography, how are the two keys used?

In public key cryptography, how are the two keys used?

• A. The recipient's private key encrypts the data; the public key decrypts.
• B. The recipient's public key encrypts the data; the recipient's private key decrypts.
• C. The same key is used for both encryption and decryption.
• D. Keys are used only for digital signatures, not encryption.

Answer: (B)

Public-key cryptography uses a pair of keys: a public key that can be shared openly and a private key that is kept secret. When you want to send a confidential message to someone, you encrypt it with that person’s public key. Anyone can encrypt in this way, but only the recipient who holds the private key can decrypt the message. This is why the correct description is that the recipient’s public key encrypts the data and the recipient’s private key decrypts. The same key isn’t used for both encryption and decryption, and public keys can also be used for digital signatures in a different use case, where the private key signs and the public key verifies.

Public-key cryptography uses a pair of keys: a public key that can be shared openly and a private key that is kept secret. When you want to send a confidential message to someone, you encrypt it with that person’s public key. Anyone can encrypt in this way, but only the recipient who holds the private key can decrypt the message. This is why the correct description is that the recipient’s public key encrypts the data and the recipient’s private key decrypts. The same key isn’t used for both encryption and decryption, and public keys can also be used for digital signatures in a different use case, where the private key signs and the public key verifies.