#include <iostream>
#include <vector>
#include <array>
#include<string>
#include<algorithm>
using namespace std;

// AES S盒（完整256个值）
const array<uint8_t, 256> s_box = {
    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
};

// 轮常数
const array<uint8_t, 10> rcon = {
    0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1B, 0x36
};

using State = array<array<uint8_t, 4>, 4>;
using RoundKey = array<uint8_t, 16>;

// 辅助函数：字节转字
uint32_t bytes_to_word(const array<uint8_t, 4>& bytes) {
    return (bytes[0] << 24) | (bytes[1] << 16) | (bytes[2] << 8) | bytes[3];
}

// 辅助函数：字转字节
array<uint8_t, 4> word_to_bytes(uint32_t word) {
    return {
        static_cast<uint8_t>(word >> 24),
        static_cast<uint8_t>((word >> 16) & 0xFF),
        static_cast<uint8_t>((word >> 8) & 0xFF),
        static_cast<uint8_t>(word & 0xFF)
    };
}

// 密钥扩展
vector<RoundKey> key_expansion(const RoundKey& key) {
    vector<RoundKey> round_keys(11);
    round_keys[0] = key;

    for (int i = 1; i <= 10; ++i) {
        RoundKey new_key;
        array<uint8_t, 4> temp;

        // 获取前一个密钥的最后4字节
        for (int j = 0; j < 4; ++j)
            temp[j] = round_keys[i - 1][j + 12];

        // RotWord
        uint8_t tmp = temp[0];
        temp[0] = temp[1];
        temp[1] = temp[2];
        temp[2] = temp[3];
        temp[3] = tmp;

        // SubWord
        for (int j = 0; j < 4; ++j)
            temp[j] = s_box[temp[j]];

        // 异或Rcon
        temp[0] ^= rcon[i - 1];

        // 生成新的轮密钥
        for (int j = 0; j < 4; ++j)
            new_key[j] = round_keys[i - 1][j] ^ temp[j];

        for (int j = 4; j < 16; ++j)
            new_key[j] = new_key[j - 4] ^ round_keys[i - 1][j];

        round_keys[i] = new_key;
    }
    return round_keys;
}

// 字节替换
void sub_bytes(State& state) {
    for (auto& row : state)
        for (auto& b : row)
            b = s_box[b];
}

// 行移位
void shift_rows(State& state) {
    // 第1行左移1字节
    uint8_t temp = state[1][0];
    state[1][0] = state[1][1];
    state[1][1] = state[1][2];
    state[1][2] = state[1][3];
    state[1][3] = temp;

    // 第2行左移2字节
    swap(state[2][0], state[2][2]);
    swap(state[2][1], state[2][3]);

    // 第3行左移3字节
    temp = state[3][3];
    state[3][3] = state[3][2];
    state[3][2] = state[3][1];
    state[3][1] = state[3][0];
    state[3][0] = temp;
}

// 有限域乘法
uint8_t gf_mult(uint8_t a, uint8_t b) {
    uint8_t res = 0;
    uint8_t hi_bit;
    for (int i = 0; i < 8; ++i) {
        if (b & 1) res ^= a;
        hi_bit = a & 0x80;
        a <<= 1;
        if (hi_bit) a ^= 0x1B; // 模x^8 + x^4 + x^3 + x + 1
        b >>= 1;
    }
    return res;
}

// 列混合
void mix_columns(State& state) {
    for (int col = 0; col < 4; ++col) {
        uint8_t a = state[0][col];
        uint8_t b = state[1][col];
        uint8_t c = state[2][col];
        uint8_t d = state[3][col];

        state[0][col] = gf_mult(a, 0x02) ^ gf_mult(b, 0x03) ^ c ^ d;
        state[1][col] = a ^ gf_mult(b, 0x02) ^ gf_mult(c, 0x03) ^ d;
        state[2][col] = a ^ b ^ gf_mult(c, 0x02) ^ gf_mult(d, 0x03);
        state[3][col] = gf_mult(a, 0x03) ^ b ^ c ^ gf_mult(d, 0x02);
    }
}

// 轮密钥加
void add_round_key(State& state, const RoundKey& key) {
    for (int i = 0; i < 4; ++i)
        for (int j = 0; j < 4; ++j)
            state[i][j] ^= key[i + 4 * j];
}

// PKCS7填充
vector<uint8_t> pkcs7_pad(const vector<uint8_t>& data) {
    size_t pad_len = 16 - (data.size() % 16);
    vector<uint8_t> padded(data);
    padded.insert(padded.end(), pad_len, static_cast<uint8_t>(pad_len));
    return padded;
}

// AES加密主函数
vector<uint8_t> aes_encrypt(const vector<uint8_t>& plaintext, const RoundKey& key) {
    auto round_keys = key_expansion(key);
    vector<uint8_t> ciphertext;

    for (size_t i = 0; i < plaintext.size(); i += 16) {
        State state;
        // 初始化状态矩阵
        for (int row = 0; row < 4; ++row)
            for (int col = 0; col < 4; ++col)
                state[row][col] = plaintext[i + row + 4 * col];

        // 初始轮密钥加
        add_round_key(state, round_keys[0]);

        // 10轮加密
        for (int round = 1; round <= 10; ++round) {
            sub_bytes(state);
            shift_rows(state);
            if (round != 10) mix_columns(state);
            add_round_key(state, round_keys[round]);
        }

        // 写入密文
        for (int row = 0; row < 4; ++row)
            for (int col = 0; col < 4; ++col)
                ciphertext.push_back(state[row][col]);
    }
    return ciphertext;
}
// 逆S盒
const array<uint8_t, 256> inv_s_box = {
    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
};

// 逆字节替换
void inv_sub_bytes(State& state) {
    for (auto& row : state)
        for (auto& b : row)
            b = inv_s_box[b];
}

// 逆行移位
void inv_shift_rows(State& state) {
    // 第1行右移1字节
    uint8_t temp = state[1][3];
    state[1][3] = state[1][2];
    state[1][2] = state[1][1];
    state[1][1] = state[1][0];
    state[1][0] = temp;

    // 第2行右移2字节
    swap(state[2][0], state[2][2]);
    swap(state[2][1], state[2][3]);

    // 第3行右移3字节
    temp = state[3][0];
    state[3][0] = state[3][1];
    state[3][1] = state[3][2];
    state[3][2] = state[3][3];
    state[3][3] = temp;
}

// 逆列混合
void inv_mix_columns(State& state) {
    for (int col = 0; col < 4; ++col) {
        uint8_t a = state[0][col];
        uint8_t b = state[1][col];
        uint8_t c = state[2][col];
        uint8_t d = state[3][col];

        state[0][col] = gf_mult(a, 0x0e) ^ gf_mult(b, 0x0b) ^ gf_mult(c, 0x0d) ^ gf_mult(d, 0x09);
        state[1][col] = gf_mult(a, 0x09) ^ gf_mult(b, 0x0e) ^ gf_mult(c, 0x0b) ^ gf_mult(d, 0x0d);
        state[2][col] = gf_mult(a, 0x0d) ^ gf_mult(b, 0x09) ^ gf_mult(c, 0x0e) ^ gf_mult(d, 0x0b);
        state[3][col] = gf_mult(a, 0x0b) ^ gf_mult(b, 0x0d) ^ gf_mult(c, 0x09) ^ gf_mult(d, 0x0e);
    }
}

// PKCS7去填充
vector<uint8_t> pkcs7_unpad(const vector<uint8_t>& data) {
    if (data.empty()) return data;
    uint8_t pad_len = data.back();
    if (pad_len > 16 || pad_len == 0) return data;
    for (size_t i = data.size() - pad_len; i < data.size(); ++i)
        if (data[i] != pad_len) return data;
    return vector<uint8_t>(data.begin(), data.end() - pad_len);
}

// AES解密主函数
vector<uint8_t> aes_decrypt(const vector<uint8_t>& ciphertext, const RoundKey& key) {
    auto round_keys = key_expansion(key);
    vector<uint8_t> plaintext;

    for (size_t i = 0; i < ciphertext.size(); i += 16) {
        State state;
        // 初始化状态矩阵
        for (int row = 0; row < 4; ++row)
            for (int col = 0; col < 4; ++col)
                state[row][col] = ciphertext[i + row + 4 * col];

        // 初始轮密钥加（使用最后一个轮密钥）
        add_round_key(state, round_keys[10]);

        // 10轮解密
        for (int round = 9; round >= 0; --round) {
            inv_shift_rows(state);
            inv_sub_bytes(state);
            add_round_key(state, round_keys[round]);
            if (round > 0) inv_mix_columns(state);
        }

        // 写入明文
        for (int row = 0; row < 4; ++row)
            for (int col = 0; col < 4; ++col)
                plaintext.push_back(state[row][col]);
    }

    // 去除填充
    return pkcs7_unpad(plaintext);
}

// 用户交互界面
void user_interface() {
    RoundKey key = {
        0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
        0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c
    };

    while (true) {
        cout << "\n=== AES-128 加解密系统 ==="
            << "\n1. 加密"
            << "\n2. 解密"
            << "\n0. 退出"
            << "\n请选择操作：";

        int choice;
        cin >> choice;
        cin.ignore(); // 清除输入缓冲

        if (choice == 0) break;

        string input;
        vector<uint8_t> data;

        switch (choice) {
        case 1: {
            cout << "请输入要加密的明文：";
            getline(cin, input);
            data = vector<uint8_t>(input.begin(), input.end());
            data = pkcs7_pad(data);

            auto cipher = aes_encrypt(data, key);
            cout << "\n加密结果（HEX）：";
            for (auto b : cipher) printf("%02x", b);
            cout << endl;
            break;
        }
        case 2: {
            cout << "请输入要解密的密文（HEX）：";
            getline(cin, input);

            // 转换HEX字符串到字节流
            data.clear();
            for (size_t i = 0; i < input.length(); i += 2) {
                string byte = input.substr(i, 2);
                data.push_back(static_cast<uint8_t>(stoul(byte, nullptr, 16)));
            }

            auto plain = aes_decrypt(data, key);
            cout << "\n解密结果：";
            for (auto b : plain) cout << static_cast<char>(b);
            cout << endl;
            break;
        }
        default:
            cout << "无效选择！" << endl;
        }
    }
}

int main() {
    user_interface();
    return 0;
}