int addRoundKey(uint8_t (*state)[4], const uint32_t *key) { uint8_t k[4][4]; /* i: row, j: col */ for (int i = 0; i < 4; ++i) { for (int j = 0; j < 4; ++j) { k[i][j] = (uint8_t) BYTE(key[j], 3 - i); /* 把 uint32 key[4] 先转换为矩阵 uint8 k[4][4] */ state[i][j] ^= k[i][j]; } } return 0; }

这段代码是AES加密中的AddRoundKey操作的实现代码。AddRoundKey是AES加密中的一个重要步骤，它的作用是将当前轮的状态矩阵与密钥进行异或操作，从而增加加密的强度。

该函数的输入参数包括一个4x4的状态矩阵state和一个长度为4的uint32_t类型的密钥key，输出结果为0。在函数中，首先定义了一个4x4的矩阵k，并通过BYTE宏将长度为4的uint32_t类型的密钥key转换为一个4x4的uint8_t类型的矩阵k。然后，对于状态矩阵中的每一个元素，都与矩阵k中相应的元素进行异或操作，最后得到的结果存储回状态矩阵中。

总的来说，AddRoundKey操作是AES加密中的一个关键步骤，它将状态矩阵与密钥进行混淆，增强加密的安全性。

相关问题

void addRoundKey(uint8_t* state, const uint8_t* roundKey)的C代码示例

这是一个AES加密算法中的函数，用于将状态矩阵与轮密钥进行异或操作。以下是一个示例代码：

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

其中，`state`是一个长度为16的uint8_t类型数组，表示AES加密算法中的状态矩阵；`roundKey`是一个长度为16的const uint8_t类型数组，表示AES加密算法中的轮密钥。该函数会将`state`数组中的每个元素与`roundKey`数组中对应位置的元素进行异或操作，结果存储在`state`数组中。

AES128_ECB_encrypt函数

下面是一个AES128_ECB_encrypt函数的示例代码，用于对输入的明文进行加密：

#include <stdint.h>

#define Nb 4
#define Nk 4
#define Nr 10

static void SubBytes(uint8_t *state);
static void ShiftRows(uint8_t *state);
static void MixColumns(uint8_t *state);
static void AddRoundKey(uint8_t *state, uint8_t *round_key);
static void KeyExpansion(uint8_t *key, uint8_t *round_key);
static void Cipher(uint8_t *input, uint8_t *output, uint8_t *round_key);

void AES128_ECB_encrypt(uint8_t *input, uint8_t *key, uint8_t *output) {
    uint8_t round_key[176];
    KeyExpansion(key, round_key);
    Cipher(input, output, round_key);
}

static uint8_t sbox[256] = {
    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
};

static void SubBytes(uint8_t *state) {
    for (int i = 0; i < Nb * 4; i++) {
        state[i] = sbox[state[i]];
    }
}

static void ShiftRows(uint8_t *state) {
    uint8_t tmp[Nb * 4];
    for (int i = 0; i < Nb * 4; i++) {
        tmp[i] = state[i];
    }
    for (int i = 0; i < Nb; i++) {
        for (int j = 0; j < 4; j++) {
            state[i * 4 + j] = tmp[(i + j) % Nb * 4 + j];
        }
    }
}

static uint8_t gf_mul(uint8_t a, uint8_t b) {
    uint8_t p = 0;
    for (int i = 0; i < 8; i++) {
        if (b & 1) {
            p ^= a;
        }
        uint8_t hi_bit = a & 0x80;
        a <<= 1;
        if (hi_bit) {
            a ^= 0x1b;
        }
        b >>= 1;
    }
    return p;
}

static void MixColumns(uint8_t *state) {
    uint8_t tmp[Nb * 4];
    for (int i = 0; i < Nb * 4; i++) {
        tmp[i] = state[i];
    }
    for (int i = 0; i < Nb; i++) {
        state[4 * i] = gf_mul(0x02, tmp[4 * i]) ^ gf_mul(0x03, tmp[4 * i + 1]) ^
                         tmp[4 * i + 2] ^ tmp[4 * i + 3];
        state[4 * i + 1] = tmp[4 * i] ^ gf_mul(0x02, tmp[4 * i + 1]) ^
                             gf_mul(0x03, tmp[4 * i + 2]) ^ tmp[4 * i + 3];
        state[4 * i + 2] = tmp[4 * i] ^ tmp[4 * i + 1] ^
                             gf_mul(0x02, tmp[4 * i + 2]) ^ gf_mul(0x03, tmp[4 * i + 3]);
        state[4 * i + 3] = gf_mul(0x03, tmp[4 * i]) ^ tmp[4 * i + 1] ^
                             tmp[4 * i + 2] ^ gf_mul(0x02, tmp[4 * i + 3]);
    }
}

static void AddRoundKey(uint8_t *state, uint8_t *round_key) {
    for (int i = 0; i < Nb * 4; i++) {
        state[i] ^= round_key[i];
    }
}

static void KeyExpansion(uint8_t *key, uint8_t *round_key) {
    uint32_t w[Nb * (Nr + 1)];
    for (int i = 0; i < Nk; i++) {
        w[i] = (key[4 * i] << 24) | (key[4 * i + 1] << 16) |
               (key[4 * i + 2] << 8) | key[4 * i + 3];
    }
    for (int i = Nk; i < Nb * (Nr + 1); i++) {
        uint32_t temp = w[i - 1];
        if (i % Nk == 0) {
            temp = (sbox[temp & 0xff] << 24) | (sbox[(temp >> 8) & 0xff] << 16) |
                   (sbox[(temp >> 16) & 0xff] << 8) | sbox[(temp >> 24) & 0xff];
            temp ^= (uint32_t)(rcon[i / Nk] << 24);
        } else if (Nk > 6 && i % Nk == 4) {
            temp = (sbox[temp & 0xff] << 24) | (sbox[(temp >> 8) & 0xff] << 16) |
                   (sbox[(temp >> 16) & 0xff] << 8) | sbox[(temp >> 24) & 0xff];
        }
        w[i] = w[i - Nk] ^ temp;
    }
    for (int i = 0; i < Nb * (Nr + 1); i++) {
        round_key[4 * i] = (w[i] >> 24) & 0xff;
        round_key[4 * i + 1] = (w[i] >> 16) & 0xff;
        round_key[4 * i + 2] = (w[i] >> 8) & 0xff;
        round_key[4 * i + 3] = w[i] & 0xff;
    }
}

static void Cipher(uint8_t *input, uint8_t *output, uint8_t *round_key) {
    uint8_t state[Nb * 4];
    for (int i = 0; i < Nb * 4; i++) {
        state[i] = input[i];
    }
    AddRoundKey(state, round_key);
    for (int round = 1; round < Nr; round++) {
        SubBytes(state);
        ShiftRows(state);
        MixColumns(state);
        AddRoundKey(state, round_key + round * Nb * 4);
    }
    SubBytes(state);
    ShiftRows(state);
    AddRoundKey(state, round_key + Nr * Nb * 4);
    for (int i = 0; i < Nb * 4; i++) {
        output[i] = state[i];
    }
}

static uint8_t rcon[11] = {
    0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c
};

该函数包含了AES128加密算法的核心实现。在函数内部，通过调用SubBytes、ShiftRows、MixColumns和AddRoundKey等辅助函数，对输入的明文进行加密处理。需要注意的是，该函数中使用了一个名为KeyExpansion的函数，用于生成扩展密钥。在实际应用中，密钥的扩展过程需要提前完成，并将扩展密钥作为参数传递给加密函数。