This is an encryption program. Modify the functions with an algorithm of a diffe

Question

This is an encryption program. Modify the functions with an algorithm of a different design to encrypt/decrypt. The functions should follow the same format as below. Just edit the contents of the encrypt/decrypt functions and jumble/unjumble the data as you see fit.They should accept a character array, combine it with the 16 byte key and manipulate it to some degree. Thank you

#include <iostream>

using namespace std;

#define BLOCK_SIZE 16

// Initialize key array, same size as data array

// The key is just an arbitary collection of bytes, it can be anything as long as they same key's used for encryption/decryption

const char key[] = "a@SDF23hds234u(D";

// Combines data bytes with key bytes then uses arbitary algorithm to jumble the data

void encrypt(char data[]) {

// Add the value of every index in the key to every index in the data array

for (int i = 0; i < BLOCK_SIZE; i++) {

data[i] = data[i] + key[i];

}

// Shift every member in the array left by 1

// So 0123456789012345 -> 1234567890123450

char first = data[0];

for (int i = 0; i < BLOCK_SIZE - 1; i++) {

data[i] = data[i + 1];

}

data[BLOCK_SIZE - 1] = first;

}

// Uses reverse of encryption algorithm to un-jumble data then seperates data bytes from key bytes

void decrypt(char data[]) {

// Shift every member in the array right by 1

// So 1234567890123450 -> 0123456789012345

char last = data[BLOCK_SIZE - 1];

for (int i = BLOCK_SIZE - 1; i >= 0; i--) {

data[i] = data[i - 1];

}

data[0] = last;

// Subtract the values of they key from the values of the data array

for (int i = 0; i < BLOCK_SIZE; i++) {

data[i] = data[i] - key[i];

}

}

int main() {

// Initialize data array

char data[] = "0123456789012345";

cout << "Encyption" << endl << endl << "[Data In]" << endl;

cout << data;

cout << endl << endl;

encrypt(data);

cout << "[Data Out]" << endl;

cout << data;

cout << endl << endl << endl;

cout << "Decryption" << endl << endl << "[Data In]" << endl;

cout << data;

cout << endl << endl;

decrypt(data);

cout << "[Data Out]" << endl;

cout << data;

cin.get();

return 0;

}

Explanation / Answer

#include <iostream>

using namespace std;

#define BLOCK_SIZE 16

// Initialize key array, same size as data array

// The key is just an arbitary collection of bytes, it can be anything as long as they same key's used for encryption/decryption

const char key[] = "a@SDF23hds234u(D";

// Combines data bytes with key bytes then uses arbitary algorithm to jumble the data

void encrypt(char data[]) {

// Add the value of every index in the key to every index in the data array

for (int i = 0; i < BLOCK_SIZE; i++) {

data[i] = data[i] + key[i];

}

for (int i = 0; i < BLOCK_SIZE; i++) {

data[i] = data[i] + 5;

}

}

// Uses reverse of encryption algorithm to un-jumble data then seperates data bytes from key bytes

void decrypt(char data[]) {

for (int i = 0; i < BLOCK_SIZE; i++) {

data[i] = data[i] - 5;

}

// Subtract the values of they key from the values of the data array

for (int i = 0; i < BLOCK_SIZE; i++) {

data[i] = data[i] - key[i];

}

}

int main() {

// Initialize data array

char data[] = "0123456789012345";

cout << "Encyption" << endl << endl << "[Data In]" << endl;

cout << data;

cout << endl << endl;

encrypt(data);

cout << "[Data Out]" << endl;

cout << data;

cout << endl << endl << endl;

cout << "Decryption" << endl << endl << "[Data In]" << endl;

cout << data;

cout << endl << endl;

decrypt(data);

cout << "[Data Out]" << endl;

cout << data;

cin.get();

return 0;

}

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