这个AES 的C 语言实现，是从linux 中port 而来，放在这里方便自己日后使用。 很容易把这个code 转为为C＋＋ 的封装。
aes.h a#ifndef __AES_H__
#define __AES_H__
#define AES_MIN_KEY_SIZE 16
#define AES_MAX_KEY_SIZE 32
#define AES_BLOCK_SIZE 16
typedef unsigned char u8;
typedef signed char s8;
typedef signed short s16;
typedef unsigned short u16;
typedef signed int s32;
typedef unsigned int u32;
typedef signed long long s64;
typedef unsigned long long u64;
typedef u16 __le16;
typedef u32 __le32;
#define E_KEY (&ctx->buf[0])
#define D_KEY (&ctx->buf[60])
#define le32_to_cpu
#define cpu_to_le32
struct aes_ctx
{
int key_length;
u32 buf[120];
};
void gen_tabs (void);
int aes_set_key(struct aes_ctx * ctx, const u8 *in_key, unsigned int key_len);
void aes_encrypt(struct aes_ctx * ctx, u8 *out, const u8 *in);
void aes_decrypt(struct aes_ctx * ctx, u8 *out, const u8 *in);
#endif
aes.c #include <stdio.h>
#include "aes.h"
static u8 pow_tab[256];
static u8 log_tab[256];
static u8 sbx_tab[256];
static u8 isb_tab[256];
static u32 rco_tab[10];
static u32 ft_tab[4][256];
static u32 it_tab[4][256];
static u32 fl_tab[4][256];
static u32 il_tab[4][256];
static inline u8 byte(const u32 x ,const unsigned n)
{
return x >> (n << 3);
}
static inline u32 rol32(u32 word, unsigned int shift)
{
return (word << shift) | (word >> (32 - shift));
}
static inline u32 ror32(u32 word, unsigned int shift)
{
return (word >> shift) | (word << (32 - shift));
}
static inline u8 f_mult(u8 a , u8 b )
{
u8 aa = log_tab[a];
u8 cc = aa + log_tab[b];
return pow_tab[cc + (cc < aa ? 1 : 0 )];
}
#define ff_mult(a,b) (a && b ? f_mult(a,b) : 0 )
#define f_rn(bo, bi, n, k)
bo[n] = ft_tab[0][byte(bi[n],0)] ^
ft_tab[1][byte(bi[(n + 1) & 3],1)] ^
ft_tab[2][byte(bi[(n + 2) & 3],2)] ^
ft_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n)
#define i_rn(bo, bi, n, k)
bo[n] = it_tab[0][byte(bi[n],0)] ^
it_tab[1][byte(bi[(n + 3) & 3],1)] ^
it_tab[2][byte(bi[(n + 2) & 3],2)] ^
it_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n)
#define ls_box(x)
( fl_tab[0][byte(x, 0)] ^
fl_tab[1][byte(x, 1)] ^
fl_tab[2][byte(x, 2)] ^
fl_tab[3][byte(x, 3)] )
#define f_rl(bo, bi, n, k)
bo[n] = fl_tab[0][byte(bi[n],0)] ^
fl_tab[1][byte(bi[(n + 1) & 3],1)] ^
fl_tab[2][byte(bi[(n + 2) & 3],2)] ^
fl_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n)
#define i_rl(bo, bi, n, k)
bo[n] = il_tab[0][byte(bi[n],0)] ^
il_tab[1][byte(bi[(n + 3) & 3],1)] ^
il_tab[2][byte(bi[(n + 2) & 3],2)] ^
il_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n)
void gen_tabs (void)
{
u32 i, t;
u8 p, q;
/* log and power tables for GF(2**8) finite field with
* 0x011b as modular polynomial - the simplest primitive
* root is 0x03, used here to generate the tables */
for (i = 0, p = 1; i < 256; ++i) {
pow_tab[i] = (u8) p;
log_tab[p] = (u8) i;
p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0);
}
log_tab[1] = 0;
for (i = 0, p = 1; i < 10; ++i) {
rco_tab[i] = p;
p = (p << 1) ^ (p & 0x80 ? 0x01b : 0);
}
for (i = 0; i < 256; ++i) {
p = (i ? pow_tab[255 - log_tab[i]] : 0);
q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2));
p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2));
sbx_tab[i] = p;
isb_tab[p] = (u8) i;
}
for (i = 0; i < 256; ++i) {
p = sbx_tab[i];
t = p;
fl_tab[0][i] = t;
fl_tab[1][i] = rol32(t, 8);
fl_tab[2][i] = rol32(t, 16);
fl_tab[3][i] = rol32(t, 24);
t = ((u32) ff_mult (2, p)) |
((u32) p << 8) |
((u32) p << 16) | ((u32) ff_mult (3, p) << 24);
ft_tab[0][i] = t;
ft_tab[1][i] = rol32(t, 8);
ft_tab[2][i] = rol32(t, 16);
ft_tab[3][i] = rol32(t, 24);
p = isb_tab[i];
t = p;
il_tab[0][i] = t;
il_tab[1][i] = rol32(t, 8);
il_tab[2][i] = rol32(t, 16);
il_tab[3][i] = rol32(t, 24);
t = ((u32) ff_mult (14, p)) |
((u32) ff_mult (9, p) << 8) |
((u32) ff_mult (13, p) << 16) |
((u32) ff_mult (11, p) << 24);
it_tab[0][i] = t;
it_tab[1][i] = rol32(t, 8);
it_tab[2][i] = rol32(t, 16);
it_tab[3][i] = rol32(t, 24);
}
}
#define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b)
#define imix_col(y,x)
u = star_x(x);
v = star_x(u);
w = star_x(v);
t = w ^ (x);
(y) = u ^ v ^ w;
(y) ^= ror32(u ^ t, 8) ^
ror32(v ^ t, 16) ^
ror32(t,24)
/* initialise the key schedule from the user supplied key */
#define loop4(i)
{ t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i];
t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t;
t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t;
t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t;
t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t;
}
#define loop6(i)
{ t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i];
t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t;
t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t;
t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t;
t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t;
t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t;
t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t;
}
#define loop8(i)
{ t = ror32(t, 8); ; t = ls_box(t) ^ rco_tab[i];
t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t;
t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t;
t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t;
t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t;
t = E_KEY[8 * i + 4] ^ ls_box(t);
E_KEY[8 * i + 12] = t;
t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t;
t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t;
t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t;
}
int aes_set_key(struct aes_ctx * ctx, const u8 *in_key, unsigned int key_len)
{
const __le32 *key = (const __le32 *)in_key;
u32 i, t, u, v, w;
if (key_len % 8 || key_len < AES_MIN_KEY_SIZE || key_len > AES_MAX_KEY_SIZE) {
return -1;
}
ctx->key_length = key_len;
E_KEY[0] = le32_to_cpu(key[0]);
E_KEY[1] = le32_to_cpu(key[1]);
E_KEY[2] = le32_to_cpu(key[2]);
E_KEY[3] = le32_to_cpu(key[3]);
switch (key_len) {
case 16:
t = E_KEY[3];
for (i = 0; i < 10; ++i)
loop4 (i);
break;
case 24:
E_KEY[4] = le32_to_cpu(key[4]);
t = E_KEY[5] = le32_to_cpu(key[5]);
for (i = 0; i < 8; ++i)
loop6 (i);
break;
case 32:
E_KEY[4] = le32_to_cpu(key[4]);
E_KEY[5] = le32_to_cpu(key[5]);
E_KEY[6] = le32_to_cpu(key[6]);
t = E_KEY[7] = le32_to_cpu(key[7]);
for (i = 0; i < 7; ++i)
loop8 (i);
break;
}
D_KEY[0] = E_KEY[0];
D_KEY[1] = E_KEY[1];
D_KEY[2] = E_KEY[2];
D_KEY[3] = E_KEY[3];
for (i = 4; i < key_len + 24; ++i) {
imix_col (D_KEY[i], E_KEY[i]);
}
return 0;
}
/* encrypt a block of text */
#define f_nround(bo, bi, k)
f_rn(bo, bi, 0, k);
f_rn(bo, bi, 1, k);
f_rn(bo, bi, 2, k);
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