use of order_key?

Hello,

What is the intended use of the order attribute “order_key”? How private this attribute should be and, theoretically, what harm could be done with it to a customer, if any?

I am developing an application using wc_api where I need to identify different orders coming in from several different Woocommerce shops. I am wondering how I should do this. I am planning to identify orders with the following string: ‘shopname_’ + id

eg. ‘coolshirtshop_123’

Would it be wise to use ‘order_key’ instead of ‘id’ in the string to identify orders coming in from the same shop? Can I trust the order ‘id’ is unique every time? Order_keys seem to be some kind of unique hash. At first glance they would seem pretty useful at distinguishing different orders.