Which statement best describes public key encryption?

Which statement best describes public key encryption?

• A. Two keys are used to encrypt and decrypt data
• B. One key used for both
• C. Uses symmetric key cryptography only
• D. Same key for encryption and decryption

Answer: (A)

Public key encryption uses a pair of keys, with a public key for encryption and a private key for decryption. This separation lets anyone send you encrypted data without sharing a secret key, and only the private key holder can read it. The defining feature is that encryption and decryption use two different keys. Using the same key for both operations would be symmetric encryption, which requires sharing a secret key in advance. The other statements describe symmetric approaches rather than public-key (asymmetric) encryption.

Public key encryption uses a pair of keys, with a public key for encryption and a private key for decryption. This separation lets anyone send you encrypted data without sharing a secret key, and only the private key holder can read it. The defining feature is that encryption and decryption use two different keys. Using the same key for both operations would be symmetric encryption, which requires sharing a secret key in advance. The other statements describe symmetric approaches rather than public-key (asymmetric) encryption.