暗号利用モード
C i = E K ( P i ⊕ C i − 1 ) , C 0 = I V {\displaystyle C_{i}=E_{K}(P_{i}\oplus C_{i-1}),C_{0}=IV}
C i = E K ( P i ⊕ P i − 1 ⊕ C i − 1 ) , P 0 ⊕ C 0 = I V {\displaystyle C_{i}=E_{K}(P_{i}\oplus P_{i-1}\oplus C_{i-1}),P_{0}\oplus C_{0}=IV}
C i = head ( E K ( S i − 1 ) , x ) ⊕ P i {\displaystyle C_{i}={\mbox{head}}(E_{K}(S_{i-1}),x)\oplus P_{i}}