Final answer:
The system administrator can use AES (Advanced Encryption Standard) for encrypting selected data on a hard drive. AES is secure and efficient, making it the best choice among the given options.
Step-by-step explanation:
The system administrator can use several types of data encryption to protect sensitive information on a hard drive. The available types mentioned in the question are:
- AES (Advanced Encryption Standard): A widely used symmetric encryption algorithm that is considered very secure and efficient. It's commonly used for encrypting data on hard drives and is an excellent choice for the system administrator.
- RSA (Rivest-Shamir-Adleman): An asymmetric encryption algorithm mainly used for secure data transmission and digital signatures. It's not typically used for encrypting data stored on hard drives.
- MD5 (Message Digest Algorithm 5): A hash function that produces a 128-bit hash value, usually used for checking the integrity of files. It's not an encryption algorithm and is not suitable for securing sensitive data.
- DES (Data Encryption Standard): An older symmetric encryption standard that has been largely replaced by AES due to vulnerabilities. Though it can encrypt data, AES is the more secure and recommended option.
Out of these options, AES is the most suitable encryption type for the system administrator to use for encrypting selected data on a hard drive.