Complexity is an adjective turned into a noun. Complex -> complexity On the other hand, complicatedness is a verb turned into an adjective turned into a noun.

Complexity is an adjective turned into a noun. Complex -> complexity On the other hand, complicatedness is a verb turned into an adjective turned into a noun. Complicate -> complicated -> complicatedness I read that as an implication that security concepts are not inherently difficult but are made difficult by people who explain it incorrectly.