What does encrypted file look like?
A well encrypted file (or data) looks like random data, there is no discernibly pattern. When you give an encrypted file to a decryption program (DCP) it tries to decrypt a small portion of the file. This part contains meta information for the DCP.
What happens when you encrypt a file?
If you encrypt files and folders in Windows, your data will become unreadable to unauthorized parties. Only someone with the correct password, or decryption key, can make the data readable again.
How does dm-crypt encrypt a Linux file system?
LUKS (Linux Unified Key Setup) is the format used on the drive itself, and is essentially used in place of a file system such as ext4. The dm-crypt system sits between the filesystem software; the filesystem software reads and writes ext4, and the ext4 data gets pushed through dm-crypt which then stores the data in LUKS format on the drive.
How to create a 512MB file in dm-crypt?
The easiest and the quickest way of going about this operation is with the fallocate command. This instantly allocates the amount of disk you would like for a file and assigns it the filename you give it. For instance, to create a 512MB file on in our root user’s home directory, we can type:
How does the dm-crypt system work with Luks?
One cool thing about the dm-crypt system is that it doesn’t have to work directly with a disk driver. Instead, it can save all the data into a single file instead of using LUKS and a whole disk partition. What that means is you can have dm-crypt create a single file within which you could create an entire file system.
How does the dm-crypt system work with ext4?
The dm-crypt system sits between the filesystem software; the filesystem software reads and writes ext4, and the ext4 data gets pushed through dm-crypt which then stores the data in LUKS format on the drive. Thus, you can effectively have a file system such as ext4 or NTFS sitting “on top of” the encrypted LUKS format.