Which encryption standard primarily focuses on data confidentiality and is a symmetric key algorithm?

The choice of AES as the answer is rooted in its design and functionality as an encryption standard. AES, or Advanced Encryption Standard, operates using symmetric key algorithms, meaning it employs the same key for both encryption and decryption processes. This characteristic emphasizes the importance of maintaining the confidentiality of data when stored or transmitted.

The primary focus of AES is to protect sensitive data by ensuring that only authorized parties, equipped with the correct key, can access the information. AES has flexible key lengths (128, 192, and 256 bits), which further enhances its security level, making it widely adopted for various applications requiring strong protection for data confidentiality.

In contrast, RSA is primarily an asymmetric encryption algorithm, which uses a pair of keys (a public key for encryption and a private key for decryption). Diffie-Hellman is also not focused on encryption for confidentiality but is a key exchange protocol that enables two parties to generate a shared secret over an insecure channel. Kerberos, while involving encryption, is fundamentally an authentication protocol designed to provide secure access and is not primarily focused on data confidentiality as its main function.