Which statement describes public-key (asymmetric) encryption?

Which statement describes public-key (asymmetric) encryption?

• A. Two different keys are used for encryption and decryption
• B. It uses the same key for encryption and decryption
• C. It cannot be used for digital signatures
• D. It requires a trusted third party to exchange keys

Answer: (A)

Public-key encryption uses a pair of keys that are related but have different roles: a public key for encryption and a private key for decryption. This means anyone can encrypt data using the recipient’s public key, but only the holder of the private key can decrypt it. That separation into two keys is the defining feature of asymmetric encryption. This is why the statement describing public-key encryption is that two different keys are used for encryption and decryption. It contrasts with symmetric encryption, where the same key is used to both encrypt and decrypt. Public-key cryptography also enables digital signatures—signing with a private key while verification is done with the public key. Regarding the need for a trusted third party, key exchange isn’t required for public-key encryption itself, though certificates from authorities may be used to bind keys to identities in practice.

Public-key encryption uses a pair of keys that are related but have different roles: a public key for encryption and a private key for decryption. This means anyone can encrypt data using the recipient’s public key, but only the holder of the private key can decrypt it. That separation into two keys is the defining feature of asymmetric encryption.

This is why the statement describing public-key encryption is that two different keys are used for encryption and decryption. It contrasts with symmetric encryption, where the same key is used to both encrypt and decrypt. Public-key cryptography also enables digital signatures—signing with a private key while verification is done with the public key. Regarding the need for a trusted third party, key exchange isn’t required for public-key encryption itself, though certificates from authorities may be used to bind keys to identities in practice.