Which term is a cryptographic algorithm for encryption and decryption?

Which term is a cryptographic algorithm for encryption and decryption?

• A. Hash
• B. Key exchange
• C. Cipher
• D. Protocol

Answer: (C)

The main idea is the term that describes the algorithm used to both encrypt and decrypt data. A cipher is exactly that: a cryptographic algorithm that takes plaintext and turns it into ciphertext using a key, and then applies the reverse operation to recover the original text. Hash functions aren’t reversible, so they don’t support decryption. Protocols describe rules for communication, not the actual encryption process. Key exchange covers how parties agree on a secret, not the data-encryption mechanism. Ciphers can be symmetric, where the same key encrypts and decrypts, or asymmetric, using related keys for different directions of the process. Examples include AES as a symmetric cipher and RSA as a public-key cipher.

The main idea is the term that describes the algorithm used to both encrypt and decrypt data. A cipher is exactly that: a cryptographic algorithm that takes plaintext and turns it into ciphertext using a key, and then applies the reverse operation to recover the original text. Hash functions aren’t reversible, so they don’t support decryption. Protocols describe rules for communication, not the actual encryption process. Key exchange covers how parties agree on a secret, not the data-encryption mechanism. Ciphers can be symmetric, where the same key encrypts and decrypts, or asymmetric, using related keys for different directions of the process. Examples include AES as a symmetric cipher and RSA as a public-key cipher.