What type of encryption is based on the use of public key infrastructure?

• A. Symmetric encryption
• B. Asymmetric encryption
• C. Hash encryption
• D. Block encryption

Answer: (B)

Asymmetric encryption is the correct answer because it fundamentally relies on a pair of keys: a public key and a private key. In this system, the public key is used for encryption, allowing anyone to encrypt a message that can only be decrypted by the corresponding private key, which is kept secure. This method is a cornerstone of public key infrastructure (PKI), which involves the management, distribution, and validation of these keys, ensuring secure communications and digital signatures.

In contrast, symmetric encryption uses the same key for both encryption and decryption, making it less suitable for scenarios such as secure exchanges over an open network, where asymmetric methods excel. Hash encryption refers to techniques that produce fixed-size hash outputs and are used primarily for integrity verification, not encryption. Block encryption is a method of processing data in fixed-size blocks but does not specify the public/private key structure essential to PKI.