Asymmetric key encryption is commonly known as what?

• A. Public key crypto, each user has a public and private key
• B. Symmetric key crypto
• C. Hash-based cryptography
• D. One-time pad

Answer: (A)

Asymmetric key encryption is about using a pair of keys, a public key and a private key. This arrangement is commonly known as public key cryptography because the public key can be shared openly while the private key remains secret. When someone wants to send you a secure message, they can encrypt it with your public key, and only your private key can decrypt it. Likewise, you can sign data with your private key, and others can verify the signature using your public key. This contrasts with symmetric key cryptography, where the same key is used to encrypt and decrypt and must be shared securely in advance. Hash-based cryptography relates to using hash functions for certain cryptographic tasks, not to public/private key pairs, and the one-time pad is a symmetric method that requires a key as long as the message and isn’t about public-key operations. Public key cryptography underpins secure key exchange and digital signatures in protocols like TLS.