（1）aes.h
#ifndef aes_h__
#define aes_h__
class AES
{
public:
AES(unsigned char* key);
virtual ~AES();
unsigned char* Cipher(unsigned char* input); // 加密，传入的数组大小必须是16字节
unsigned char* InvCipher(unsigned char* input); // 解密，传入的数组也必须是16字节
void* Cipher(void* input, int length=0); // 可以传入数组，大小必须是16的整数倍，如果不是将会越界操作；如果不传length而默认为0，那么将按照字符串处理，遇'\0'结束
void* InvCipher(void* input, int length); // 必须传入数组和大小，必须是16的整数倍
private:
unsigned char Sbox[256];
unsigned char InvSbox[256];
unsigned char w[11][4][4];
void KeyExpansion(unsigned char* key, unsigned char w[][4][4]);
unsigned char FFmul(unsigned char a, unsigned char b);
void SubBytes(unsigned char state[][4]);
void ShiftRows(unsigned char state[][4]);
void MixColumns(unsigned char state[][4]);
void AddRoundKey(unsigned char state[][4], unsigned char k[][4]);
void InvSubBytes(unsigned char state[][4]);
void InvShiftRows(unsigned char state[][4]);
void InvMixColumns(unsigned char state[][4]);
};
#endif // aes_h__（2）aes.cpp
#include "aes.h"
#include "string.h"
AES::AES(unsigned char* key)
{
unsigned char sBox[] =
{ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
0x63,0x7c,0x77,0x7b,0xf2,0x6b,0x6f,0xc5,0x30,0x01,0x67,0x2b,0xfe,0xd7,0xab,0x76, /*0*/
0xca,0x82,0xc9,0x7d,0xfa,0x59,0x47,0xf0,0xad,0xd4,0xa2,0xaf,0x9c,0xa4,0x72,0xc0, /*1*/
0xb7,0xfd,0x93,0x26,0x36,0x3f,0xf7,0xcc,0x34,0xa5,0xe5,0xf1,0x71,0xd8,0x31,0x15, /*2*/
0x04,0xc7,0x23,0xc3,0x18,0x96,0x05,0x9a,0x07,0x12,0x80,0xe2,0xeb,0x27,0xb2,0x75, /*3*/
0x09,0x83,0x2c,0x1a,0x1b,0x6e,0x5a,0xa0,0x52,0x3b,0xd6,0xb3,0x29,0xe3,0x2f,0x84, /*4*/
0x53,0xd1,0x00,0xed,0x20,0xfc,0xb1,0x5b,0x6a,0xcb,0xbe,0x39,0x4a,0x4c,0x58,0xcf, /*5*/
0xd0,0xef,0xaa,0xfb,0x43,0x4d,0x33,0x85,0x45,0xf9,0x02,0x7f,0x50,0x3c,0x9f,0xa8, /*6*/
0x51,0xa3,0x40,0x8f,0x92,0x9d,0x38,0xf5,0xbc,0xb6,0xda,0x21,0x10,0xff,0xf3,0xd2, /*7*/
0xcd,0x0c,0x13,0xec,0x5f,0x97,0x44,0x17,0xc4,0xa7,0x7e,0x3d,0x64,0x5d,0x19,0x73, /*8*/
0x60,0x81,0x4f,0xdc,0x22,0x2a,0x90,0x88,0x46,0xee,0xb8,0x14,0xde,0x5e,0x0b,0xdb, /*9*/
0xe0,0x32,0x3a,0x0a,0x49,0x06,0x24,0x5c,0xc2,0xd3,0xac,0x62,0x91,0x95,0xe4,0x79, /*a*/
0xe7,0xc8,0x37,0x6d,0x8d,0xd5,0x4e,0xa9,0x6c,0x56,0xf4,0xea,0x65,0x7a,0xae,0x08, /*b*/
0xba,0x78,0x25,0x2e,0x1c,0xa6,0xb4,0xc6,0xe8,0xdd,0x74,0x1f,0x4b,0xbd,0x8b,0x8a, /*c*/
0x70,0x3e,0xb5,0x66,0x48,0x03,0xf6,0x0e,0x61,0x35,0x57,0xb9,0x86,0xc1,0x1d,0x9e, /*d*/
0xe1,0xf8,0x98,0x11,0x69,0xd9,0x8e,0x94,0x9b,0x1e,0x87,0xe9,0xce,0x55,0x28,0xdf, /*e*/
0x8c,0xa1,0x89,0x0d,0xbf,0xe6,0x42,0x68,0x41,0x99,0x2d,0x0f,0xb0,0x54,0xbb,0x16 /*f*/
};
unsigned char invsBox[256] =
{ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
0x52,0x09,0x6a,0xd5,0x30,0x36,0xa5,0x38,0xbf,0x40,0xa3,0x9e,0x81,0xf3,0xd7,0xfb, /*0*/
0x7c,0xe3,0x39,0x82,0x9b,0x2f,0xff,0x87,0x34,0x8e,0x43,0x44,0xc4,0xde,0xe9,0xcb, /*1*/
0x54,0x7b,0x94,0x32,0xa6,0xc2,0x23,0x3d,0xee,0x4c,0x95,0x0b,0x42,0xfa,0xc3,0x4e, /*2*/
0x08,0x2e,0xa1,0x66,0x28,0xd9,0x24,0xb2,0x76,0x5b,0xa2,0x49,0x6d,0x8b,0xd1,0x25, /*3*/
0x72,0xf8,0xf6,0x64,0x86,0x68,0x98,0x16,0xd4,0xa4,0x5c,0xcc,0x5d,0x65,0xb6,0x92, /*4*/
0x6c,0x70,0x48,0x50,0xfd,0xed,0xb9,0xda,0x5e,0x15,0x46,0x57,0xa7,0x8d,0x9d,0x84, /*5*/
0x90,0xd8,0xab,0x00,0x8c,0xbc,0xd3,0x0a,0xf7,0xe4,0x58,0x05,0xb8,0xb3,0x45,0x06, /*6*/
0xd0,0x2c,0x1e,0x8f,0xca,0x3f,0x0f,0x02,0xc1,0xaf,0xbd,0x03,0x01,0x13,0x8a,0x6b, /*7*/
0x3a,0x91,0x11,0x41,0x4f,0x67,0xdc,0xea,0x97,0xf2,0xcf,0xce,0xf0,0xb4,0xe6,0x73, /*8*/
0x96,0xac,0x74,0x22,0xe7,0xad,0x35,0x85,0xe2,0xf9,0x37,0xe8,0x1c,0x75,0xdf,0x6e, /*9*/
0x47,0xf1,0x1a,0x71,0x1d,0x29,0xc5,0x89,0x6f,0xb7,0x62,0x0e,0xaa,0x18,0xbe,0x1b, /*a*/
0xfc,0x56,0x3e,0x4b,0xc6,0xd2,0x79,0x20,0x9a,0xdb,0xc0,0xfe,0x78,0xcd,0x5a,0xf4, /*b*/
0x1f,0xdd,0xa8,0x33,0x88,0x07,0xc7,0x31,0xb1,0x12,0x10,0x59,0x27,0x80,0xec,0x5f, /*c*/
0x60,0x51,0x7f,0xa9,0x19,0xb5,0x4a,0x0d,0x2d,0xe5,0x7a,0x9f,0x93,0xc9,0x9c,0xef, /*d*/
0xa0,0xe0,0x3b,0x4d,0xae,0x2a,0xf5,0xb0,0xc8,0xeb,0xbb,0x3c,0x83,0x53,0x99,0x61, /*e*/
0x17,0x2b,0x04,0x7e,0xba,0x77,0xd6,0x26,0xe1,0x69,0x14,0x63,0x55,0x21,0x0c,0x7d /*f*/
};
memcpy(Sbox, sBox, 256);
memcpy(InvSbox, invsBox, 256);
KeyExpansion(key, w);
}
AES::~AES()
{
}
unsigned char* AES::Cipher(unsigned char* input)
{
unsigned char state[4][4];
int i,r,c;
for(r=0; r<4; r++)
{
for(c=0; c<4 ;c++)
{
state[r][c] = input[c*4+r];
}
}
AddRoundKey(state,w[0]);
for(i=1; i<=10; i++)
{
SubBytes(state);
ShiftRows(state);
if(i!=10)MixColumns(state);
AddRoundKey(state,w[i]);
}
for(r=0; r<4; r++)
{
for(c=0; c<4 ;c++)
{
input[c*4+r] = state[r][c];
}
}
return input;
}
unsigned char* AES::InvCipher(unsigned char* input)
{
unsigned char state[4][4];
int i,r,c;
for(r=0; r<4; r++)
{
for(c=0; c<4 ;c++)
{
state[r][c] = input[c*4+r];
}
}
AddRoundKey(state, w[10]);
for(i=9; i>=0; i--)
{
InvShiftRows(state);
InvSubBytes(state);
AddRoundKey(state, w[i]);
if(i)
{
InvMixColumns(state);
}
}
for(r=0; r<4; r++)
{
for(c=0; c<4 ;c++)
{
input[c*4+r] = state[r][c];
}
}
return input;
}
void* AES::Cipher(void* input, int length)
{
unsigned char* in = (unsigned char*) input;
int i;
if(!length) // 如果是0则当做字符串处理
{
while(*(in+length++));
in = (unsigned char*) input;
}
for(i=0; i<length; i+=16)
{
Cipher(in+i);
}
return input;
}
void* AES::InvCipher(void* input, int length)
{
unsigned char* in = (unsigned char*) input;
int i;
for(i=0; i<length; i+=16)
{
InvCipher(in+i);
}
return input;
}
void AES::KeyExpansion(unsigned char* key, unsigned char w[][4][4])
{
int i,j,r,c;
unsigned char rc[] = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36};
for(r=0; r<4; r++)
{
for(c=0; c<4; c++)
{
w[0][r][c] = key[r+c*4];
}
}
for(i=1; i<=10; i++)
{
for(j=0; j<4; j++)
{
unsigned char t[4];
for(r=0; r<4; r++)
{
t[r] = j ? w[i][r][j-1] : w[i-1][r][3];
}
if(j == 0)
{
unsigned char temp = t[0];
for(r=0; r<3; r++)
{
t[r] = Sbox[t[(r+1)%4]];
}
t[3] = Sbox[temp];
t[0] ^= rc[i-1];
}
for(r=0; r<4; r++)
{
w[i][r][j] = w[i-1][r][j] ^ t[r];
}
}
}
}
unsigned char AES::FFmul(unsigned char a, unsigned char b)
{
unsigned char bw[4];
unsigned char res=0;
int i;
bw[0] = b;
for(i=1; i<4; i++)
{
bw[i] = bw[i-1]<<1;
if(bw[i-1]&0x80)
{
bw[i]^=0x1b;
}
}
for(i=0; i<4; i++)
{
if((a>>i)&0x01)
{
res ^= bw[i];
}
}
return res;
}
void AES::SubBytes(unsigned char state[][4])
{
int r,c;
for(r=0; r<4; r++)
{
for(c=0; c<4; c++)
{
state[r][c] = Sbox[state[r][c]];
}
}
}
void AES::ShiftRows(unsigned char state[][4])
{
unsigned char t[4];
int r,c;
for(r=1; r<4; r++)
{
for(c=0; c<4; c++)
{
t[c] = state[r][(c+r)%4];
}
for(c=0; c<4; c++)
{
state[r][c] = t[c];
}
}
}
void AES::MixColumns(unsigned char state[][4])
{
unsigned char t[4];
int r,c;
for(c=0; c< 4; c++)
{
for(r=0; r<4; r++)
{
t[r] = state[r][c];
}
for(r=0; r<4; r++)
{
state[r][c] = FFmul(0x02, t[r])
^ FFmul(0x03, t[(r+1)%4])
^ FFmul(0x01, t[(r+2)%4])
^ FFmul(0x01, t[(r+3)%4]);
}
}
}
void AES::AddRoundKey(unsigned char state[][4], unsigned char k[][4])
{
int r,c;
for(c=0; c<4; c++)
{
for(r=0; r<4; r++)
{
state[r][c] ^= k[r][c];
}
}
}
void AES::InvSubBytes(unsigned char state[][4])
{
int r,c;
for(r=0; r<4; r++)
{
for(c=0; c<4; c++)
{
state[r][c] = InvSbox[state[r][c]];
}
}
}
void AES::InvShiftRows(unsigned char state[][4])
{
unsigned char t[4];
int r,c;
for(r=1; r<4; r++)
{
for(c=0; c<4; c++)
{
t[c] = state[r][(c-r+4)%4];
}
for(c=0; c<4; c++)
{
state[r][c] = t[c];
}
}
}
void AES::InvMixColumns(unsigned char state[][4])
{
unsigned char t[4];
int r,c;
for(c=0; c< 4; c++)
{
for(r=0; r<4; r++)
{
t[r] = state[r][c];
}
for(r=0; r<4; r++)
{
state[r][c] = FFmul(0x0e, t[r])
^ FFmul(0x0b, t[(r+1)%4])
^ FFmul(0x0d, t[(r+2)%4])
^ FFmul(0x09, t[(r+3)%4]);
}
}
}上面的加密算法是没问题的，但是接口有两个需要注意的地方，也就是在头文件中备注的地方：
1、数组的大小必须是16字节或者16的整数倍。
2、不能直接使用字符串输出，因为加密后的数组内容可能有'\0'，字符串会被截断。
为了更方便的使用此加密算法，封装了一个接口类，声明如下：
（3）AESEncryptor.h
#ifndef AES_Encryptor_h__
#define AES_Encryptor_h__
#include <string>
class AES;
class AesEncryptor
{
public:
AesEncryptor(unsigned char* key);
~AesEncryptor(void);
std::string EncryptString(std::string strInfor);
std::string DecryptString(std::string strMessage);
void EncryptTxtFile(const char* inputFileName, const char* outputFileName);
void DecryptTxtFile(const char* inputFileName, const char* outputFileName);
private:
void Byte2Hex(const unsigned char* src, int len, char* dest);
void Hex2Byte(const char* src, int len, unsigned char* dest);
int Char2Int(char c);
private:
AES* m_pEncryptor;
};
#endif // AES_Encryptor_h__
#include "aes.h"
#include "AESEncryptor.h"
//#include "log.h"
#include <fstream>
using namespace std;
AesEncryptor::AesEncryptor(unsigned char* key)
{
m_pEncryptor = new AES(key);
}
AesEncryptor::~AesEncryptor(void)
{
delete m_pEncryptor;
}
void AesEncryptor::Byte2Hex(const unsigned char* src, int len, char* dest) {
for (int i=0; i<len; ++i) {
sprintf_s(dest + i * 2, 3, "%02X", src[i]);
}
}
void AesEncryptor::Hex2Byte(const char* src, int len, unsigned char* dest) {
int length = len / 2;
for (int i=0; i<length; ++i) {
dest[i] = Char2Int(src[i * 2]) * 16 + Char2Int(src[i * 2 + 1]);
}
}
int AesEncryptor::Char2Int(char c) {
if ('0' <= c && c <= '9') {
return (c - '0');
}
else if ('a' <= c && c<= 'f') {
return (c - 'a' + 10);
}
else if ('A' <= c && c<= 'F') {
return (c - 'A' + 10);
}
return -1;
}
string AesEncryptor::EncryptString(string strInfor)
{
int nLength = strInfor.length();
int spaceLength = 16 - (nLength % 16);
unsigned char* pBuffer = new unsigned char[nLength + spaceLength];
memset(pBuffer, '\0', nLength + spaceLength);
memcpy_s(pBuffer, nLength + spaceLength, strInfor.c_str(), nLength);
m_pEncryptor->Cipher(pBuffer, nLength + spaceLength);
// 这里需要把得到的字符数组转换成十六进制字符串
char* pOut = new char[2 * (nLength + spaceLength)];
memset(pOut, '\0', 2 * (nLength + spaceLength));
Byte2Hex(pBuffer, nLength + spaceLength, pOut);
string retValue(pOut);
delete[] pBuffer;
//delete[] pOut;
return retValue;
}
string AesEncryptor::DecryptString(string strMessage) {
int nLength = strMessage.length() / 2;
unsigned char* pBuffer = new unsigned char[nLength];
memset(pBuffer, '\0', nLength);
Hex2Byte(strMessage.c_str(), strMessage.length(), pBuffer);
m_pEncryptor->InvCipher(pBuffer, nLength);
string retValue((char*)pBuffer);
delete[] pBuffer;
return retValue;
}
void AesEncryptor::EncryptTxtFile(const char* inputFileName, const char* outputFileName) {
ifstream ifs;
// Open file:
ifs.open(inputFileName);
if (!ifs) {
//UNILOGW("AesEncryptor::EncryptTxtFile() - Open input file failed!");
return ;
}
// Read config data:
string strInfor;
string strLine;
while (!ifs.eof()) {
char temp[1024];
memset(temp, '\0', 1024);
ifs.read(temp, 1000);
strInfor += temp;
}
ifs.close();
// Encrypt
strLine = EncryptString(strInfor);
// Writefile
ofstream ofs;
ofs.open(outputFileName);
if (!ofs) {
//UNILOGW("AesEncryptor::EncryptTxtFile() - Open output file failed!");
return ;
}
ofs << strLine;
ofs.close();
}
void AesEncryptor::DecryptTxtFile(const char* inputFile, const char* outputFile) {
ifstream ifs;
// Open file:
ifs.open(inputFile);
if (!ifs) {
//UNILOGW("AesEncryptor::DecryptTxtFile() - Open input file failed!");
return ;
}
// Read config data:
string strInfor;
string strLine;
while (!ifs.eof()) {
char temp[1024];
memset(temp, '\0', 1024);
ifs.read(temp, 1000);
strInfor += temp;
}
ifs.close();
// Encrypt
strLine = DecryptString(strInfor);
// Writefile
ofstream ofs;
ofs.open(outputFile);
if (!ofs) {
//UNILOGW("AesEncryptor::DecryptTxtFile() - Open output file failed!");
return ;
}
ofs << strLine;
ofs.close();
}从代码中可以看到增加了以下特性：
1、支持对std::string 字符串类型的加密，并返回相应的字符串，这个字符串是将加密后的内容转换成十六进制表示的，所以不存在截断的问题。当然了，解密的时候也需要转换成真正的unsigned char数组；
2、支持直接对文本文件进行加密，指定输入和输出的文件名即可。
（5）main.cpp#include <iostream>
#include <string>
#include "AESEncryptor.h"
int main()
{
unsigned char src[4] = {0x28, 0x7e, 0x88, 0x16};
AesEncryptor aesE(src);
std::string strInfor = "你好";
std::string encryptS = aesE.EncryptString(strInfor);
std::string decryptS = aesE.DecryptString(encryptS);
system("pause");
return 0;
}