What type of encryption does the Data Encryption Standard (DES) use?

The correct answer highlights that the Data Encryption Standard (DES) utilizes publicly available algorithms, combined with confidential keys to secure data. DES is a symmetric key algorithm, which means it uses the same key for both encryption and decryption. The algorithm itself is widely known and publicly documented, allowing for scrutiny and examination by cryptographers and security professionals. However, the strength of its encryption lies in the secrecy and complexity of the key used.

The approach of mixing publicly known algorithms with private keys ensures that, while the method of encryption is accessible for review and analysis to maintain its integrity, the actual key used to encrypt data must be kept confidential to prevent unauthorized access. This combination is what characterizes DES and sets it apart as an efficient symmetric encryption standard during its time.

Entities using DES must ensure that the confidentiality of their encryption keys is maintained, as knowledge of the keys is crucial for the protection of the encrypted data. Hence, understanding the role of both the public nature of the algorithm and the private nature of the keys is essential in assessing the security provided by DES.