Javier is concerned about sensitive data on his hard drive, he is going to use AES based symmetric encryption to quickly password protect the data.
AES, or Advanced Encryption Standard, was widely adopted as a new encryption standard in 2001. By using AES, Javier can encrypt his data and password protect it. AES comes in three encryption strengths: 128, 192, and 256. AES 256 is the strongest of the three encryption types and is very hard to crack.
This site explains a bit more about AES and how to use it.