Setting up Sticky Session on AWS ELB for Prestashop

i am currently toying around with my shop hoping that i can load balance my shop.

I basically want to use the sticky session feature for my load balancer (see image below):

Unfortunately i don't know what value should i put here. This is basically where i am stuck with. As far as i know, prestashop encrypt cookies information (both name and value).

Here's a screenshot:

I have got a hunch that somehow i need to hard-code it in such a way that i creates a new cookie name and associated with a unique value for a particular session.

Can anyone help me with this? What should i do?

FYI: I am using Prestashop 1.5.4.x