Create partition for swap (/dev/sdaX in this example). Prepare and enable it using mkswap and swapon commands. If you already use swap partition then omit these steps.
$ sudo mkswap /dev/sdaX
Setting up swapspace version 1, size = 4194300 KiB
no label, UUID=325d9718-8532-460d-afec-74e6aee9ae5f
$ sudo swapon /dev/sdaX
Execute ecryptfs-setup-swap script (it is part of ecryptfs-utils package):
$ sudo ecryptfs-setup-swap
WARNING:
An encrypted swap is required to help ensure that encrypted files are not leaked
to disk in an unencrypted format.
HOWEVER, THE SWAP ENCRYPTION CONFIGURATION PRODUCED BY THIS PROGRAM
WILL BREAK HIBERNATE/RESUME ON THIS SYSTEM!
NOTE: Your suspend/resume capabilities will not be affected.
Do you want to proceed with encrypting your swap? [y/N]: y
INFO: Setting up swap: [/dev/sdaX]
* Stopping remaining crypto disks...
* cryptswap1 (stopped)... [ OK ]
* Starting remaining crypto disks...
* cryptswap1 (starting)..
* cryptswap1 (started)... [ OK ]
INFO: Successfully setup encrypted swap!
Changes are automatically applied to crypttab and fstab configuration files.
$ cat /etc/crypttab | grep /dev/sdaX
cryptswap1 /dev/sdaX /dev/urandom swap,cipher=aes-cbc-essiv:sha256
$ cat /etc/fstab | grep cryptswap1
/dev/mapper/cryptswap1 none swap sw 0 0
