Задание:
Напишите на языке C++ программу для зашифрования и расшифрования
сообщения по «МАГМА».
Выполнение работы:
Программа выполнена на Visual Studio.
Листинг программы:
#include <iostream>
#include <cmath>
using namespace std;
typedef unsigned long long ullong;
typedef unsigned long ulong;
//64b
//32b
class int256 {
ullong bits[4];
public:
int256(ullong b0, ullong b1, ullong b2, ullong b3) :bits{ b0, b1, b2,
b3 } {}
ullong get(int i) {
return bits[i];
}
};
class Magma {
int256 key;
ullong mod32 = 0xffffffff;
ulong keys[8];
ulong xkey[32];
int n;
const int piBlock[8][16] = {
{1, 7, 14, 13, 0, 5, 8, 3, 4, 15, 10, 6, 9, 12, 11, 2},
{8, 14, 2, 5, 6, 9, 1, 12, 15, 4, 11, 0, 13, 10, 3, 7},
{5, 13, 15, 6, 9, 2, 12, 10, 11, 7, 8, 1, 4, 3, 14, 0},
{7, 15, 5, 10, 8, 1, 6, 13, 0, 9, 3, 14, 11, 4, 2, 12},
{12, 8, 2, 1, 13, 4, 15, 6, 7, 0, 10, 5, 3, 14, 9, 11},
{11, 3, 5, 8, 2, 15, 10, 13, 14, 1, 7, 4, 12, 9, 6, 0},
{6, 8, 2, 3, 9, 10, 5, 12, 1, 14, 4, 7, 11, 13, 0, 15},
{12, 4, 6, 2, 10, 5, 11, 9, 14, 8, 13, 7, 0, 3, 15, 1},
};
void setKeys() {
for (int i = 0; i < 4; ++i) {
ullong left = key.get(i);
ullong right = left & mod32;
left >>= 32;
keys[i * 2] = left;
keys[i * 2 + 1] = right;
}
}
ulong f(ullong a, ullong x, int pi) {
a += x;
a &= mod32;
int un[8];
for (int i = 0; i < 8; ++i) {
x = a & 0xf;//4 numbers
un[8 - i - 1] = x;
a >>= 4;
}
for (int i = 0; i < 8; ++i) {
un[i] = piBlock[i][un[i]];
}
for (int i = 0; i < 8; ++i) {
a += un[i];
a <<= 4;
}
a >>= 4;
a = (a << 11) | (a >> 21);
a &= mod32;
return a;
}
ullong round(ullong& left, ullong& right) {
ullong old;
//cout << "start: " << left << ' ' << right << endl;
for (int i = 0; i < 31; ++i) {
old = right;//remember old right value
right = left ^ f(right, xkey[i], i);//xor
left = old;
//cout << left << ' ' << right << endl;
}
//last round, 32
left = left ^ f(right, xkey[31], 31);
//cout << left << ' ' << right << endl;
left <<= 32;
left += right;
return left;
}
void setXkey() {
n = 0;
for (int i = 0; i < 24; ++i) {
xkey[i] = keys[i % 8];
n = n + 1;
printf("k%d=",n);
cout << xkey[i] << endl;
}
n = 24;
for (int i = 7; i >= 0; --i) {
xkey[32 - i - 1] = keys[i];
2
n = n + 1;
printf("k%d=", n);
cout << xkey[i] << endl;
}
}
public:
Magma(int256 key) : key{ key } {
setKeys();
}
ullong encrypt(ullong data) {
ullong left = data;
ullong right = left & mod32;
left >>= 32;
setXkey();
data = round(left, right);
return data;
}
ullong decrypt(ullong data) {
ullong left = data;
ullong right = left & mod32;
left >>= 32;
setXkey();
//reverse xkey
for (int i = 8; i < 16; ++i) {
std::swap(xkey[i], xkey[32 - i - 1]);
}
data = round(left, right);
return data;
}
int256 getKey() {
return key;
}
};
int main() {
setlocale(LC_ALL, "RUSSIAN");
cout << hex;
int256 key(0xffeeddccbbaa9988, 0x7766554433221100,
0xf0f1f2f3f4f5f6f7, 0xf8f9fafbfcfdfeff);
Magma a(key);
ullong text = 0xfedcba9876543210;
cout << "\nТекст для щифрования = " << text << endl;
cout << "\nИтерационные ключи шифрования:" << endl;;
ullong encrypt_text = a.encrypt(text);
cout << "\nЗашифрованный текст = " << encrypt_text << endl<< endl;
ullong decrypt_text = a.decrypt(encrypt_text);
cout << "\nТекст обратно расшифрованный = " << decrypt_text << endl;
return 0;
}
3
Результат выполнения программы:
4