所以我一直在尝试在C中实现AES-256。经过大量的阅读并在维基百科页面之后实现它，我设法编写它。只有当我测试它时，它似乎给出了错误的输出。
代码：
/*
AES-256
(c) 2017 Daniel Gee
*/
#include <stdio.h>
#include <stdlib.h>
unsigned char rcon[256] = {
0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a,
0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39,
0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a,
0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8,
0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef,
0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc,
0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b,
0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3,
0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94,
0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20,
0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35,
0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f,
0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04,
0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63,
0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd,
0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d
};
unsigned char 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
};
void rotate(unsigned char *w){
unsigned char t;
t = w[0];
w[0] = w[1];
w[1] = w[2];
w[2] = w[3];
w[3] = t;
}
void key_schedule_core(unsigned char *w, unsigned char i){
unsigned char j;
rotate(w);
for(j = 0; j < 4; j++){
w[j] = sbox[w[j]];
}
w[0] ^= rcon[i];
}
unsigned char *key_schedule(unsigned char *key){
unsigned char n = 32, b = 240, *e = malloc(sizeof(unsigned char) * b), i = 1, j, k, t[4];
for(k = 0; k < n; k++){
e[k] = key[k];
}
j = 32;
while(j < b){
t[0] = e[j - 4];
t[1] = e[j - 3];
t[2] = e[j - 2];
t[3] = e[j - 1];
key_schedule_core(t, i);
i++;
t[0] ^= e[j - n];
t[1] ^= e[j - n + 1];
t[2] ^= e[j - n + 2];
t[3] ^= e[j - n + 3];
e[j] = t[0];
e[j + 1] = t[1];
e[j + 2] = t[2];
e[j + 3] = t[3];
j += 4;
for(k = 0; k < 3; k++){
t[0] = e[j - 4];
t[1] = e[j - 3];
t[2] = e[j - 2];
t[3] = e[j - 1];
t[0] ^= e[j - n];
t[1] ^= e[j - n + 1];
t[2] ^= e[j - n + 2];
t[3] ^= e[j - n + 3];
e[j] = t[0];
e[j + 1] = t[1];
e[j + 2] = t[2];
e[j + 3] = t[3];
j += 4;
}
t[0] = e[j - 4];
t[1] = e[j - 3];
t[2] = e[j - 2];
t[3] = e[j - 1];
t[0] = sbox[t[0]];
t[1] = sbox[t[1]];
t[2] = sbox[t[2]];
t[3] = sbox[t[3]];
t[0] ^= e[j - n];
t[1] ^= e[j - n + 1];
t[2] ^= e[j - n + 2];
t[3] ^= e[j - n + 3];
e[j] = t[0];
e[j + 1] = t[1];
e[j + 2] = t[2];
e[j + 3] = t[3];
j += 4;
if(j > b){
break;
}
for(k = 0; k < 3; k++){
t[0] = e[j - 4];
t[1] = e[j - 3];
t[2] = e[j - 2];
t[3] = e[j - 1];
t[0] ^= e[j - n];
t[1] ^= e[j - n + 1];
t[2] ^= e[j - n + 2];
t[3] ^= e[j - n + 3];
e[j] = t[0];
e[j + 1] = t[1];
e[j + 2] = t[2];
e[j + 3] = t[3];
j += 4;
}
}
return e;
}
void shift_rows(unsigned char *state){
unsigned char t;
t = state[4];
state[4] = state[5];
state[5] = state[6];
state[6] = state[7];
state[7] = t;
t = state[8];
state[10] = t;
t = state[9];
state[11] = t;
t = state[12];
state[12] = state[15];
state[15] = state[14];
state[14] = state[13];
state[13] = t;
}
void mix_columns(unsigned char *state){
unsigned char a[4], b[4], c, j;
for(j = 0; j < 4; j++){
for(c = 0; c < 4; c++){
a[c] = state[(j * 4) + c];
b[c] = state[(j * 4) + c] << 1;
if(state[(j * 4) + c] & 0x80){
b[c] ^= 0x1b;
}
}
state[(j * 4) + 0] = b[0] ^ a[3] ^ a[2] ^ b[1] ^ a[1];
state[(j * 4) + 1] = b[1] ^ a[0] ^ a[3] ^ b[2] ^ a[2];
state[(j * 4) + 2] = b[2] ^ a[1] ^ a[0] ^ b[3] ^ a[3];
state[(j * 4) + 3] = b[3] ^ a[2] ^ a[1] ^ b[0] ^ a[0];
}
}
void encrypt(unsigned char *key, unsigned char *state){
unsigned char *e = key_schedule(key), i, j;
for(i = 0; i < 14; i++){
if(i == 0){
for(j = 0; j < 16; j++){
state[j] ^= e[(i * 16) + j];
}
}else if(i == 13){
for(j = 0; j < 16; j++){
state[j] ^= sbox[state[j]];
}
shift_rows(state);
for(j = 0; j < 16; j++){
state[j] ^= e[(i * 16) + j];
}
}else{
for(j = 0; j < 16; j++){
state[j] ^= sbox[state[j]];
}
shift_rows(state);
mix_columns(state);
for(j = 0; j < 16; j++){
state[j] ^= e[(i * 16) + j];
}
}
}
}
int main(){
unsigned char key[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
message[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
encrypt(key, message);
for(int i = 0; i < 16; i++){
printf("%02x ", message[i]);
}
printf("\n");
}
示例：
key = 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
message = 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
output = c2 2a 26 68 a8 4a 1e f3 ac 40 23 05 25 50 00 02
答案 0 :(得分：2)
这本书＆＃34; Rijndael的设计＆＃34; （ISBN 3-540-42580-2）在附录D中有一个很好的测试向量列表，用于AES 128加密的所有中间步骤。逐步执行您的代码，并将结果与本书中的结果进行比较。应该很容易将代码临时更改为AES-128以查找错误，然后再将其切换回AES-256。
之后，丢弃您的实现并使用经过全面测试的已建立的实现，因为您的实时攻击（因为<span class="fa fa-life-ring"></span>
.fa {
transform: translateY(-4%);
}
）容易受到攻击者的攻击，因此攻击者可以找到密钥。要避免这种情况和其他实现错误，请查阅一本关于实现加密的书籍，并尝试使用尽可能多的预先存在的代码，而不是编写自己的代码。