I would kike to ask a question regarding the article "the" in the following sentence.
"This is to ensure that (the) public keys belonging to (the) external parties are not affected."
(1) Are these two articles (the) required? (Suppose that we have not discussed about those public keys and external parties beforehand.)
(2) What are the general rules that apply in deciding whether or not to use "the" in these two places?