Android's security model is defense-in-depth: several independent layers must each fail before an attack reaches your data, so the overall block probability compounds rather than adds. With each active layer i catching a fraction pᵢ of attacks on its own, the chance an attack gets through every active layer is the product of each layer's miss rate, so P(block) = 1 − ∏ᵢ (1 − pᵢ) Turn a layer OFF and its factor drops out of the product — the security score falls sharply, not gradually, which is why disabling SELinux or skipping encryption is so much riskier than the single percentage might suggest. AES-256 intercepts more than AES-128 because a longer key makes brute-force and offline data-extraction attacks far less likely to succeed before the device is wiped or recovered.