AES.cpp

#include <iostream>
#include <cstring>
#include <cmath>
using namespace std;
#define ROUND 10
#define MAX_LENGTH 1000

const uint8_t Sbox[16][16] = {
    0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,
    0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,
    0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,
    0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75,
    0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0, 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84,
    0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,
    0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8,
    0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5, 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2,
    0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,
    0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB,
    0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C, 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79,
    0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,
    0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A,
    0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E, 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E,
    0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,
    0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16};

const uint8_t re_Sbox[16][16] = {
    0x52, 0x09, 0x6A, 0xD5, 0x30, 0x36, 0xA5, 0x38, 0xBF, 0x40, 0xA3, 0x9E, 0x81, 0xF3, 0xD7, 0xFB,
    0x7C, 0xE3, 0x39, 0x82, 0x9B, 0x2F, 0xFF, 0x87, 0x34, 0x8E, 0x43, 0x44, 0xC4, 0xDE, 0xE9, 0xCB,
    0x54, 0x7B, 0x94, 0x32, 0xA6, 0xC2, 0x23, 0x3D, 0xEE, 0x4C, 0x95, 0x0B, 0x42, 0xFA, 0xC3, 0x4E,
    0x08, 0x2E, 0xA1, 0x66, 0x28, 0xD9, 0x24, 0xB2, 0x76, 0x5B, 0xA2, 0x49, 0x6D, 0x8B, 0xD1, 0x25,
    0x72, 0xF8, 0xF6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xD4, 0xA4, 0x5C, 0xCC, 0x5D, 0x65, 0xB6, 0x92,
    0x6C, 0x70, 0x48, 0x50, 0xFD, 0xED, 0xB9, 0xDA, 0x5E, 0x15, 0x46, 0x57, 0xA7, 0x8D, 0x9D, 0x84,
    0x90, 0xD8, 0xAB, 0x00, 0x8C, 0xBC, 0xD3, 0x0A, 0xF7, 0xE4, 0x58, 0x05, 0xB8, 0xB3, 0x45, 0x06,
    0xD0, 0x2C, 0x1E, 0x8F, 0xCA, 0x3F, 0x0F, 0x02, 0xC1, 0xAF, 0xBD, 0x03, 0x01, 0x13, 0x8A, 0x6B,
    0x3A, 0x91, 0x11, 0x41, 0x4F, 0x67, 0xDC, 0xEA, 0x97, 0xF2, 0xCF, 0xCE, 0xF0, 0xB4, 0xE6, 0x73,
    0x96, 0xAC, 0x74, 0x22, 0xE7, 0xAD, 0x35, 0x85, 0xE2, 0xF9, 0x37, 0xE8, 0x1C, 0x75, 0xDF, 0x6E,
    0x47, 0xF1, 0x1A, 0x71, 0x1D, 0x29, 0xC5, 0x89, 0x6F, 0xB7, 0x62, 0x0E, 0xAA, 0x18, 0xBE, 0x1B,
    0xFC, 0x56, 0x3E, 0x4B, 0xC6, 0xD2, 0x79, 0x20, 0x9A, 0xDB, 0xC0, 0xFE, 0x78, 0xCD, 0x5A, 0xF4,
    0x1F, 0xDD, 0xA8, 0x33, 0x88, 0x07, 0xC7, 0x31, 0xB1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xEC, 0x5F,
    0x60, 0x51, 0x7F, 0xA9, 0x19, 0xB5, 0x4A, 0x0D, 0x2D, 0xE5, 0x7A, 0x9F, 0x93, 0xC9, 0x9C, 0xEF,
    0xA0, 0xE0, 0x3B, 0x4D, 0xAE, 0x2A, 0xF5, 0xB0, 0xC8, 0xEB, 0xBB, 0x3C, 0x83, 0x53, 0x99, 0x61,
    0x17, 0x2B, 0x04, 0x7E, 0xBA, 0x77, 0xD6, 0x26, 0xE1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0C, 0x7D};

const uint8_t mixMatrix[4][4] = {
    0x02, 0x03, 0x01, 0x01,
    0x01, 0x02, 0x03, 0x01,
    0x01, 0x01, 0x02, 0x03,
    0x03, 0x01, 0x01, 0x02};

const uint8_t re_mixMatrix[4][4] = {
    0x0E, 0x0B, 0x0D, 0x09,
    0x09, 0x0E, 0x0B, 0x0D,
    0x0D, 0x09, 0x0E, 0x0B,
    0x0B, 0x0D, 0x09, 0x0E};

const uint8_t Rcon[10] = {
    0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1B, 0x36};

uint8_t key[16] = {
    1, 1, 4, 5,
    1, 4, 1, 9,
    1, 9, 8, 1,
    0, 2, 3, 3};
uint8_t subKeys[ROUND + 1][16] = {};

void keyGen(uint8_t *key) // generate 128-bit keys for 10 rounds
{
    memcpy(subKeys[0], key, 16);
    for (int r = 1; r <= ROUND; r++)
    {
        uint8_t temp[4];
        for (int i = 0; i < 4; i++)
        {
            temp[i] = Sbox[subKeys[r - 1][(i + 1) % 4 + 12] >> 4][subKeys[r - 1][(i + 1) % 4 + 12] & 0x0F];
        }
        temp[0] ^= Rcon[r];
        for (int i = 0; i < 4; i++)
        {
            subKeys[r][i] = subKeys[r - 1][i] ^ temp[i];
        }
        for (int i = 4; i < 16; i++)
        {
            subKeys[r][i] = subKeys[r - 1][i] ^ subKeys[r][i - 4];
        }
    }
}

void addRoundKey(uint8_t *block, uint8_t *key)
{
    for (int i = 0; i < 16; i++)
    {
        block[i] ^= key[i];
    }
}

void subByte(uint8_t *block)
{
    for (int i = 0; i < 16; i++)
    {
        block[i] = Sbox[block[i] >> 4][block[i] & 0x0F];
    }
}

void re_subByte(uint8_t *block)
{
    for (int i = 0; i < 16; i++)
    {
        block[i] = re_Sbox[block[i] >> 4][block[i] & 0x0F];
    }
}

void shiftRows(uint8_t *block)
{
    uint8_t temp[16] = {};
    memcpy(temp, block, 16);
    for (int i = 0; i < 16; i++)
    {
        switch (i % 4)
        {
        case 0:
            block[i] = temp[i];
            break;
        case 1:
            block[i] = temp[(i + 4) % 16];
            break;
        case 2:
            block[i] = temp[(i + 8) % 16];
            break;
        case 3:
            block[i] = temp[(i + 12) % 16];
            break;
        }
    }
}

void re_shiftRows(uint8_t *block)
{
    uint8_t temp[16] = {};
    memcpy(temp, block, 16);
    for (int i = 0; i < 16; i++)
    {
        switch (i % 4)
        {
        case 0:
            block[i] = temp[i];
            break;
        case 1:
            block[i] = temp[(i + 12) % 16];
            break;
        case 2:
            block[i] = temp[(i + 8) % 16];
            break;
        case 3:
            block[i] = temp[(i + 4) % 16];
            break;
        }
    }
}

uint8_t GaloisMult(uint8_t L, uint8_t R) // multiplication in GF(2^7)
{
    uint8_t product = 0;
    while (L)
    {
        if (L & 0x01)
        {
            product ^= R;
        }
        L >>= 1;
        if (R & 0x80)
        {
            R <<= 1;
            R ^= 0x1B;
        }
        else
        {
            R <<= 1;
        }
    }
    return product;
}

void mixColumn(uint8_t *block)
{
    uint8_t temp[16] = {};
    memcpy(temp, block, 16);
    for (int i = 0; i < 4; i++)
    {
        for (int j = 0; j < 4; j++)
        {
            block[i + j * 4] =
                GaloisMult(mixMatrix[i][0], temp[j * 4]) ^
                GaloisMult(mixMatrix[i][1], temp[j * 4 + 1]) ^
                GaloisMult(mixMatrix[i][2], temp[j * 4 + 2]) ^
                GaloisMult(mixMatrix[i][3], temp[j * 4 + 3]);
        }
    }
}

void re_mixColumn(uint8_t *block)
{
    uint8_t temp[16] = {};
    memcpy(temp, block, 16);
    for (int i = 0; i < 4; i++)
    {
        for (int j = 0; j < 4; j++)
        {
            block[i + j * 4] =
                GaloisMult(re_mixMatrix[i][0], temp[j * 4]) ^
                GaloisMult(re_mixMatrix[i][1], temp[j * 4 + 1]) ^
                GaloisMult(re_mixMatrix[i][2], temp[j * 4 + 2]) ^
                GaloisMult(re_mixMatrix[i][3], temp[j * 4 + 3]);
        }
    }
}

void aes_encryption(uint8_t *block)
{
    addRoundKey(block, subKeys[0]);
    for (int r = 1; r <= ROUND; r++)
    {
        subByte(block);
        shiftRows(block);
        if (r != ROUND)
        {
            mixColumn(block);
        }
        addRoundKey(block, subKeys[r]);
    }
}

void aes_decryption(uint8_t *block)
{

    for (int r = ROUND; r >= 1; r--)
    {
        addRoundKey(block, subKeys[r]);
        if (r != ROUND)
        {
            re_mixColumn(block);
        }
        re_shiftRows(block);
        re_subByte(block);
    }
    addRoundKey(block, subKeys[0]);
}

void printByteMatrix(uint8_t *block)
{
    for (int i = 0; i < 4; i++)
    {
        for (int j = 0; j < 4; j++)
        {
            printf("%d ", block[i + j * 4]);
        }
        cout << endl;
    }
}

int main()
{
    keyGen(key);
    // for (int r = 0; r < ROUND + 1; r++)
    // {
    //     cout << "roundKey " << r << " :" << endl;
    //     printByteMatrix(subKeys[r]);
    //     cout << endl;
    // }

    // uint8_t msg[16] = {
    //     0, 1, 2, 3,
    //     4, 5, 6, 7,
    //     8, 9, 10, 11,
    //     12, 13, 14, 15};

    // cout << "message:" << endl;
    // printByteMatrix(msg);

    // aes_encryption(msg);
    // cout << "ciphertext:" << endl;
    // printByteMatrix(msg);

    // aes_decryption(msg);
    // cout << "plaintext:" << endl;
    // printByteMatrix(msg);

    char message[MAX_LENGTH] = "";
    char ciphertext[MAX_LENGTH] = "";
    char plaintext[MAX_LENGTH] = "";
    int t = 20;
    while (t--)
    {
        cout<<"\nPlease input the message:\n";
        memset(message, '\0', sizeof(message));
        memset(ciphertext, '\0', sizeof(ciphertext));
        memset(plaintext, '\0', sizeof(plaintext));
        cin >> message;
        int length = strlen(message);
        int pad = 16 - (length % 16);
        if (pad == 16) {
            pad = 0;
        }
        for (int i = length; i < length + pad; i++) {
            message[i] = pad;
        }
        length += pad;
        int num = length / 16;

        for (int i = 0; i < num; i++)
        {
            uint8_t block[16] = {0};
            memcpy(block, message + i * 16, 16);
            printf("\nmessage-block %d\n", i);
            printByteMatrix(block);

            aes_encryption(block);
            memcpy(ciphertext + i * 16, block, 16);
            printf("\nciphertext-block %d\n", i);
            printByteMatrix(block);

            aes_decryption(block);
            memcpy(plaintext + i * 16, block, 16);
            printf("\nplaintext-block %d\n", i);
            printByteMatrix(block);
        }
        ciphertext[length] = '\0';
        plaintext[length] = '\0';

        // cout<<endl<<length<<" "<<strlen(ciphertext)<<" "<<strlen(plaintext)<<endl;
        printf("\nciphertext:\n%s\n", ciphertext);
        printf("\nplaintext:\n%s\n", plaintext);
    }
}