I wanted to encrypt my Documents. My home folder is on a logical volume. So I made some space by removing another logical volume and creating a new one, which gets encrypted by cryptsetup. Here are the commands:
lvdisplay
Display all logical volumes on the systemlvremove defaultvolumegroup/data
Remove the logical volume "data" from the volume group "defaultvolumegroup"lvcreate -L 53.66G --name data defaultvolumegroup
Create the logical volume "data" with a size of 53.66 GB in the volume group "defaultvolumegroup"cryptsetup create cryptodata /dev/mapper/defaultvolumegroup-data
Create the encrypted device "/dev/mapper/cryptodata"mkfs.ext3 /dev/mapper/cryptodata
Format the device with the ext3 file systemmount /dev/mapper/cryptodata /home/jeltsch/data
Mount the device