Ubuntu live persistent mode + encrypt

Hi all,

I use: “Ubuntu v16.04 Mate 64bit” on the USB flash drive, which is divided into two partitions (1, Ubuntu ISO Live)+(2, “casper-rw” persistent mode)
Use home directory encryption…
(Because the complete installation of Ubuntu + LUKS encryption is too demanding on the USB Flash Drive)

I want to move on “Ubuntu v18.04 Mate 64bit”… (Unfortunately, there is no support for home directory encryption)
Is there any possibility how, encrypt casper-rw ? Example: (casper-rw + LUKS ?)

Thx.

PS:
I started new Ubuntu Mate 18.04 in persistent mode: http://prntscr.com/jhbthd
I don’t know default username and password…

I do not work these combinations:
root
ubuntu
mate
ubuntu-mate