Which of the following statements about public-key cryptography is true?

• A. It is symmetric
• B. It is based on shared secrets
• C. It is asymmetric
• D. It does not use algorithms

Answer: (C)

Public-key cryptography is characterized by its use of asymmetric key pairs, consisting of a public key and a private key. The public key can be shared openly and is used to encrypt data, while the private key is kept secret and is used for decryption. This fundamental difference from symmetric cryptography, which relies on a single shared secret key for both encryption and decryption, makes public-key cryptography particularly useful for secure communications over untrusted networks.

Due to its asymmetric nature, public-key cryptography enables functionalities such as digital signatures and secure key exchanges without needing a prior shared secret between the communicating parties. This is crucial in establishing secure connections in various applications, such as SSL/TLS for web security.

Understanding the characteristics of public-key cryptography highlights its unique advantages and applications in information security, confirming the correctness of the statement regarding its asymmetric nature.