DES.cpp

#include <iostream>
#include <bitset>

using namespace std;

bitset<64> key;                // 64-bit key
bitset<48> roundKeys[16];      // 16 48-bit keys generated from the original key

// Initial Permutation Table
int initial_permutation[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 };

// Inverse Initial Permutation Table
int inverse_initial_permutation[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 };

// ... (other tables and functions for DES)

bitset<64> DES(bitset<64>& plaintext) {
    bitset<64> ciphertext;
    // Initial Permutation
    bitset<64> initial_permuted_text;
    for(int i=0; i<64; i++) {
        initial_permuted_text[63-i] = plaintext[64-initial_permutation[i]];
    }
    // 16 rounds of DES
    for(int round=0; round<16; round++) {
        // ... (DES round operations)
    }
    // Inverse Initial Permutation
    for(int i=0; i<64; i++) {
        ciphertext[63-i] = initial_permuted_text[64-inverse_initial_permutation[i]];
    }
    return ciphertext;
}

int main() {
    bitset<64> plaintext;
    cout << "Enter 64-bit plaintext in binary: ";
    cin >> plaintext;
    bitset<64> ciphertext = DES(plaintext);
    cout << "Ciphertext: " << ciphertext << endl;
    return 0;
}