## encrypt swap partition

sources :
* [wiki.archlinux.org - dm-crypt/Swap encryption](https://wiki.archlinux.org/index.php/Dm-crypt/Swap_encryption#LVM_on_LUKS)
* [help.ubuntu.com - Enable Hibernate With Encrypted Swap](https://help.ubuntu.com/community/EnableHibernateWithEncryptedSwap)

~~~
apt-get install ecryptfs-utils
swapoff -a
cryptsetup luksFormat --cipher aes-xts-plain64 --verify-passphrase --key-size 256 /dev/nvme0n1p2
cryptsetup open /dev/<device> cryptswap
mkswap /dev/mapper/mkswap /dev/mapper/cryptswap
~~~

edit : /etc/default/grub

~~~
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash resume=UUUUUUU"
~~~

~~~
update-grub
~~~

Now ajust /etc/fstab to use your mapper, replace your encrypt swap device like bellow :

~~~
/dev/mapper/cryptswap   none   swap   discard   0   0
~~~

add your encrypt swap device define in /etc/crypttab

~~~
cryptswap   /dev/nvme0n1p2		none	luks
~~~

~~~
swapon -a
~~~

Register these changes.

~~~
update-initramfs -u -k all
~~~

### to be solve

~~~
cryptsetup: ERROR: Couln't resolve device rpool/ROOT/ubuntu_...
cryptsetup: WARNING: Couln't determine root device
~~~

## disable encrypt swap partition

* Turn off swap

~~~
swapoff /dev/mapper/cryptswap1
~~~

* remove your encrypt swap device define in your /etc/crypttab 

* ajust /etc/fstab to use your real swap partition 

~~~
/dev/nvme0n1p2   none   swap   discard   0   0
~~~

* Change your /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT to

~~~
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash resume=/dev/nvme0n1p2"
~~~

~~~
update-grub
~~~

* edit /etc/initramfs-tools/conf.d/resume. Replace the existing RESUME line with the following line.

~~~
RESUME=/dev/nvme0n1p2
~~~

Register these changes.

~~~
update-initramfs -u -k all
~~~

* make your partition a swap

~~~
mkswap /dev/nvme0n1p2
~~~

* activate swap

~~~
swapon -a
~~~