How to setup the use of a USB pen drive as a key for an ecryptfs private directory

Partition and format the USB stick

If it's not already done, you'll want to partition and format a filesystem to be used to hold the key data from ecryptfs:

 # fdisk /dev/sdb
 # mkfs.ext3 /dev/sdb1

Copy your .ecryptfs to the USB stick

Mount the pen drive on a temporary path, then copy .ecryptfs from your home directory to the temporary mountpoint.

 # mount /dev/sdb1 /mnt
 # cp -a /home/USERNAME/.ecryptfs/* /mnt
 # umount /mnt

Obtain the device's UUID

This step is required for automatizing the mounting of the pen drive to the proper path on boot.

 # blkid /dev/sdb1

Automatize

To mount on boot

Add the following line to /etc/fstab to mount the USB pen drive to the proper directory on boot:

 UUID=<UUID from blkid> /home/<username>/.ecryptfs          ext3     relatime        0       2

To mount on connection

There has to be a way to do this...