Status: IN
Memento achieves encapsulation-preserving state externalization through a layered access architecture: the two-interface design (narrow for Caretaker, wide for Originator) is the mechanism that enforces both the encapsulation guarantee and the Caretaker's opacity constraint, ensuring state can be captured, transferred, and restored without any intermediary accessing internal details.
Three independently specified Memento properties (encapsulation preservation, dual interface design, caretaker opacity) converge on a single architectural mechanism — layered access control
Depends on (SL): memento-captures-state-preserving-encapsulation, memento-two-interfaces-narrow-and-wide, memento-caretaker-never-examines-contents