$ sudo apt-get update
$ sudo apt-get install libjs-jsencrypt 

libjs-jsencrypt is installed in your system.

Make ensure the libjs-jsencrypt package were installed using the commands given below,

$ sudo dpkg-query -l | grep libjs-jsencrypt *

You will get with libjs-jsencrypt package name, version, architecture and description in a table

libjs-jsencrypt package basic information: