帮我解析一下这段代码int keyExpansion(const uint8_t key, uint32_t keyLen, AesKey aesKey) { if (NULL == key || NULL == aesKey){ return -1; } if (keyLen != 16){ return -1; }

这段代码是一个用于对密钥进行扩展的函数。让我们逐行解析它：

1. `int keyExpansion(const uint8_t* key, uint32_t keyLen, AesKey aesKey)`: 这是函数的定义，它接受一个指向uint8_t类型的密钥数组，一个表示密钥长度的整数keyLen和一个AesKey类型的结构体aesKey作为参数，并返回一个整数。

2. `if (NULL == key || NULL == aesKey) { return -1; }`: 这是一个条件判断语句，检查传入的密钥指针和aesKey结构体是否为NULL。如果其中任何一个为NULL，则返回-1，表示函数执行失败。

3. `if (keyLen != 16) { return -1; }`: 这是另一个条件判断语句，检查传入的密钥长度是否等于16。如果不等于16，则返回-1，表示函数执行失败。

该函数的目的是对给定的密钥进行扩展，并将扩展后的结果存储在aesKey结构体中。根据代码的上下文，我们可以推断出该函数是用于AES加密算法的密钥扩展部分。但是，由于代码片段中没有给出完整的函数实现，我们无法提供更多关于函数内部逻辑的解析。

相关问题

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。

写一个aes加密算法的代码

以下是一个简单的 AES 加密算法的代码示例：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>

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

typedef uint8_t state_t[4][4];

static const uint8_t sbox[256] = {
// S-box
};

static const uint8_t rsbox[256] = {
// Inverse S-box
};

static const uint8_t Rcon[11] = {
// Round constants
};

static void sub_bytes(state_t *state)
{
// SubBytes step
}

static void shift_rows(state_t *state)
{
// ShiftRows step
}

static void mix_columns(state_t *state)
{
// MixColumns step
}

static void add_round_key(uint8_t round, state_t *state, const uint8_t *key)
{
// AddRoundKey step
}

static void key_expansion(const uint8_t *key, uint8_t *w)
{
// KeyExpansion routine
}

void aes_encrypt(const uint8_t *in, uint8_t *out, const uint8_t *key)
{
state_t state;
uint8_t w[4 * Nb * (Nr + 1)];

key_expansion(key, w);

memcpy(state, in, 4 * Nb);

add_round_key(0, &state, key);

for (uint8_t round = 1; round < Nr; ++round) {
sub_bytes(&state);
shift_rows(&state);
mix_columns(&state);
add_round_key(round, &state, w + round * 4 * Nb);
}

sub_bytes(&state);
shift_rows(&state);
add_round_key(Nr, &state, w + Nr * 4 * Nb);

memcpy(out, state, 4 * Nb);
}

int main(void)
{
uint8_t in[16] = { /* Input data */ };
uint8_t out[16];
uint8_t key[16] = { /* Key */ };

aes_encrypt(in, out, key);

for (int i = 0; i < 16; ++i) {
printf("%02x ", out[i]);
}
printf("\n");

return 0;
}