One-timePadk=1001110001010111m= 1100010100101101=0101100101111010Cm= 1100010100101101
One-time Pad k = 1001110001010111 m = 1100010100101101 c = 0101100101111010 m = 1100010100101101
1.1StreamCyphersPseudorandom Generator (PRG)[0,1]s→[0,1]nn >>sInitialization Vector (Iv)E(k, m) = m ④ PRG(k, IV)D(k, c) = C ④ PRG(k, IV)
1.1 Stream Cyphers Pseudorandom Generator (PRG) {0, 1}s → {0, 1}n n >> s Initialization Vector (IV) E(k, m) = m ⊕ PRG(k, IV) D(k, c) = c ⊕ PRG(k, IV)
1.2 Block CyphersDES3-DESAES
1.2 Block Cyphers • DES • 3-DES • AES
1.2.1 Mode of OperationECBCBCCFBCTR
1.2.1 Mode of Operation • ECB • CBC • CFB • CTR