Disk encryption

- [Instructor] If you don't want someone to easily read…or alter the data on your system's disk,…then you should encrypt it.…When you encrypt your data,…it looks like a large blob of random data.…For example, if you were to encrypt the text, letmein123,…it might look like the seemingly random series of letters…and numbers displayed on your screen.…The OS can't operate on this nonsensical data.…So after you encrypt your data,…you need to allow the operating system and its applications…access to that data in a way that can be understood by them.…

In short, the OS needs access to the decrypted…or unlocked form of that data.…To unlock the encrypted data, a user needs to supply…some sort of secret information.…This can be a passphrase or a keyfile.…In some cases, this passphrase or key is used to encrypt…and decrypt the data.…In other cases, it's used to unlock the master key…that is used to do the actual encryption and decryption.…In any case, it's stored in memory…for as long as the encrypted device is mounted.…