Fig. 4

Mission time (MT) for the same reliability as that of 〈1,0〉, under sequential attack. The horizontal axis measures the MT (τ) of the reference system 〈1,0〉. Each curve is associated with an intrusion tolerance thresholdf, but is independent of the replication degreen. The vertical axis measures another MT (τ′), such that, if the curve associated with 〈n,f〉 includes point 〈τ,τ′〉, then \(\mathcal{R}_{n,f}^{\therefore }(\tau') = \mathcal {R}_{1,0}^{\therefore }(\tau)\). Curve a (), with f=0, is the identity τ=τ′