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DES Encryption - Introduction to Cryptography Homework 2 - 0816146 韋詠祥
Raw
DES-Key-Plaintext.txt
12345678 Advanced
Testkey1 Hello CS
00000000 Galois!!
STANDARD Classics
Learning 12345678
Enigma!! security
Raw
DES.cpp
#include <iostream>
#include <fstream>
#include <cstring>
#define CIPHER_ONLY false
/*
* DES Encryption
*
* Introduction to Cryptography Homework #2
*
* Source Code: https://git.io/DES
*
* 2021-03-17 by Sean, 0816146 韋詠祥
*/
using namespace std;
string encDES(string keyStr, string txtStr);
int main() {
clock_t begin, end;
double cpu_time_used;
string line, key, txt, enc;
ifstream in;
ofstream out;
begin = clock();
in.open("DES-Key-Plaintext.txt");
out.open("out.txt");
while (getline(in, line)) {
key = line.substr(0, 8);
txt = line.substr(9, 8);
enc = encDES(key, txt);
if (CIPHER_ONLY)
out << enc << '\n';
else
out << key << ' ' << txt << ' ' << enc << '\n';
}
in.close(); out.close();
end = clock();
cpu_time_used = ((double) (end - begin)) / CLOCKS_PER_SEC;
printf("CPU Time used: %f\n", cpu_time_used);
return 0;
}
/*
* ========== BEGIN OF CONSTANTS ==========
*/
static const char hex_digits[17] = "0123456789ABCDEF";
static const int table_ip[64] = {
58, 50, 42, 34, 26, 18, 10, 2,
60, 52, 44, 36, 28, 20, 12, 4,
62, 54, 46, 38, 30, 22, 14, 6,
64, 56, 48, 40, 32, 24, 16, 8,
57, 49, 41, 33, 25, 17, 9, 1,
59, 51, 43, 35, 27, 19, 11, 3,
61, 53, 45, 37, 29, 21, 13, 5,
63, 55, 47, 39, 31, 23, 15, 7
};
static const int table_fp[64] = {
40, 8, 48, 16, 56, 24, 64, 32,
39, 7, 47, 15, 55, 23, 63, 31,
38, 6, 46, 14, 54, 22, 62, 30,
37, 5, 45, 13, 53, 21, 61, 29,
36, 4, 44, 12, 52, 20, 60, 28,
35, 3, 43, 11, 51, 19, 59, 27,
34, 2, 42, 10, 50, 18, 58, 26,
33, 1, 41, 9, 49, 17, 57, 25
};
static const int table_pc1[56] = {
57, 49, 41, 33, 25, 17, 9,
1, 58, 50, 42, 34, 26, 18,
10, 2, 59, 51, 43, 35, 27,
19, 11, 3, 60, 52, 44, 36,
63, 55, 47, 39, 31, 23, 15,
7, 62, 54, 46, 38, 30, 22,
14, 6, 61, 53, 45, 37, 29,
21, 13, 5, 28, 20, 12, 4
};
static const int table_pc2[48] = {
14, 17, 11, 24, 1, 5,
3, 28, 15, 6, 21, 10,
23, 19, 12, 4, 26, 8,
16, 7, 27, 20, 13, 2,
41, 52, 31, 37, 47, 55,
30, 40, 51, 45, 33, 48,
44, 49, 39, 56, 34, 53,
46, 42, 50, 36, 29, 32
};
static const int table_e[48] = {
32, 1, 2, 3, 4, 5,
4, 5, 6, 7, 8, 9,
8, 9, 10, 11, 12, 13,
12, 13, 14, 15, 16, 17,
16, 17, 18, 19, 20, 21,
20, 21, 22, 23, 24, 25,
24, 25, 26, 27, 28, 29,
28, 29, 30, 31, 32, 1
};
static const int table_p[32] = {
16, 7, 20, 21, 29, 12, 28, 17,
1, 15, 23, 26, 5, 18, 31, 10,
2, 8, 24, 14, 32, 27, 3, 9,
19, 13, 30, 6, 22, 11, 4, 25
};
static const int table_s[8][4][16] = {
{
{14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7},
{0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8},
{4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0},
{15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13}
},
{
{15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10},
{3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5},
{0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15},
{13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9}
},
{
{10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8},
{13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1},
{13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7},
{1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12}
},
{
{7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15},
{13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9},
{10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4},
{3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14}
},
{
{2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9},
{14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6},
{4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14},
{11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3}
},
{
{12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11},
{10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8},
{9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6},
{4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13}
},
{
{4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1},
{13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6},
{1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2},
{6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12}
},
{
{13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7},
{1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2},
{7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8},
{2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11}
}
};
/*
* ========== BEGIN OF HELPER FUNCTIONS ==========
*/
/* Rotate two half block */
void rot(bool CiDi[56], const int round) {
char tmpL, tmpR;
int flag = !(round == 0 || round == 1 || round == 8 || round == 15);
do {
tmpL = CiDi[0], tmpR = CiDi[28];
for (int i=0; i<55; i++)
CiDi[i] = CiDi[i+1];
CiDi[27] = tmpL, CiDi[55] = tmpR;
} while (flag--);
}
/* XOR for binary array */
const bool *xor_bin(const bool *A, const bool *B, const int len) {
bool *C = new bool[len];
for (int i=0; i<len; i++)
C[i] = A[i]^B[i];
return C;
}
/* Feistel */
const bool *F(const bool R[32], const bool key[48]) {
/* Expansion */
bool *resE = new bool[48];
for (int i=0; i<48; i++)
resE[i] = R[table_e[i]-1];
/* Exclusive-OR */
const bool *resX = xor_bin(resE, key, 48);
/* Substitution */
bool *resS = new bool[32];
for (int i=0, j=0, k=0; i<48; i+=6) {
int row = resX[i]<<1 | resX[i+5];
int col = resX[i+1]<<3 | resX[i+2]<<2 | resX[i+3]<<1 | resX[i+4];
int value = table_s[j++][row][col];
for (int x=8; x>0; x>>=1)
resS[k++] = (value & x) ? 1 : 0;
}
/* Permutation */
bool *resP = new bool[32];
for (int i=0; i<32; i++)
resP[i] = resS[table_p[i]-1];
return resP;
}
/* Iterate */
void iter(bool txtBin[64], const bool subKey[48]) {
bool oldL[32], oldR[32];
memcpy(oldL, txtBin, 32);
memcpy(oldR, &txtBin[32], 32);
const bool *fstl = F(oldR, subKey);
const bool *newR = xor_bin(oldL, fstl, 32);
memcpy(txtBin, oldR, 32);
memcpy(&txtBin[32], newR, 32);
}
string encDES(const string keyStr, const string txtStr) {
bool keyBin[64], txtBin[64], tmpBin[64];
bool subBin[48], CiDi[56];
/* String to Binary */
for (int i=0, k=0; i<8; i++)
for (int j=128; j>0; j>>=1) {
keyBin[k] = (keyStr[i] & j) ? 1 : 0;
txtBin[k] = (txtStr[i] & j) ? 1 : 0;
k++;
}
/* Initial Permutation */
for (int i=0; i<64; i++)
tmpBin[i] = txtBin[table_ip[i]-1];
memcpy(txtBin, tmpBin, 64);
/* Permuted Choice 1 */
for (int i=0; i<56; i++)
CiDi[i] = keyBin[table_pc1[i]-1];
/* Encryption Rounds */
for (int round=0; round<16; round++) {
rot(CiDi, round);
for (int i=0; i<48; i++)
subBin[i] = CiDi[table_pc2[i]-1];
iter(txtBin, subBin);
}
/* 32-bit Swap */
memcpy(tmpBin, txtBin, 32);
memcpy(txtBin, &txtBin[32], 32);
memcpy(&txtBin[32], tmpBin, 32);
/* Final Permutation */
for (int i=0; i<64; i++)
tmpBin[i] = txtBin[table_fp[i]-1];
memcpy(txtBin, tmpBin, 64);
/* Convert binary to hex */
string encStr;
for (int i=0; i<64; i+=4)
encStr += hex_digits[ txtBin[i+0]<<3 | txtBin[i+1]<<2 | txtBin[i+2]<<1 | txtBin[i+3] ];
return encStr;
}
Raw
out.txt
12345678 Advanced AE184796707E59FB
Testkey1 Hello CS C29E28FFDD018F11
00000000 Galois!! DCE6E7099CE53DFC
STANDARD Classics 0969EAA031E36D95
Learning 12345678 1EBEB7B57DF58CDB
Enigma!! security FE74785A4C3CCC36
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