我从网上下载了一套AES加密算法的C++实现,代码如下:
(1)aes.h
#ifndef SRC_UTILS_AES_H #define SRC_UTILS_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 // SRC_UTILS_AES_H
(2)aes.cpp
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
1 #include "aes.h" 2 #include "string.h" 3 4 AES::AES(unsigned char* key) 5 { 6 unsigned char sBox[] = 7 { /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ 8 0x63,0x7c,0x77,0x7b,0xf2,0x6b,0x6f,0xc5,0x30,0x01,0x67,0x2b,0xfe,0xd7,0xab,0x76, /*0*/ 9 0xca,0x82,0xc9,0x7d,0xfa,0x59,0x47,0xf0,0xad,0xd4,0xa2,0xaf,0x9c,0xa4,0x72,0xc0, /*1*/ 10 0xb7,0xfd,0x93,0x26,0x36,0x3f,0xf7,0xcc,0x34,0xa5,0xe5,0xf1,0x71,0xd8,0x31,0x15, /*2*/ 11 0x04,0xc7,0x23,0xc3,0x18,0x96,0x05,0x9a,0x07,0x12,0x80,0xe2,0xeb,0x27,0xb2,0x75, /*3*/ 12 0x09,0x83,0x2c,0x1a,0x1b,0x6e,0x5a,0xa0,0x52,0x3b,0xd6,0xb3,0x29,0xe3,0x2f,0x84, /*4*/ 13 0x53,0xd1,0x00,0xed,0x20,0xfc,0xb1,0x5b,0x6a,0xcb,0xbe,0x39,0x4a,0x4c,0x58,0xcf, /*5*/ 14 0xd0,0xef,0xaa,0xfb,0x43,0x4d,0x33,0x85,0x45,0xf9,0x02,0x7f,0x50,0x3c,0x9f,0xa8, /*6*/ 15 0x51,0xa3,0x40,0x8f,0x92,0x9d,0x38,0xf5,0xbc,0xb6,0xda,0x21,0x10,0xff,0xf3,0xd2, /*7*/ 16 0xcd,0x0c,0x13,0xec,0x5f,0x97,0x44,0x17,0xc4,0xa7,0x7e,0x3d,0x64,0x5d,0x19,0x73, /*8*/ 17 0x60,0x81,0x4f,0xdc,0x22,0x2a,0x90,0x88,0x46,0xee,0xb8,0x14,0xde,0x5e,0x0b,0xdb, /*9*/ 18 0xe0,0x32,0x3a,0x0a,0x49,0x06,0x24,0x5c,0xc2,0xd3,0xac,0x62,0x91,0x95,0xe4,0x79, /*a*/ 19 0xe7,0xc8,0x37,0x6d,0x8d,0xd5,0x4e,0xa9,0x6c,0x56,0xf4,0xea,0x65,0x7a,0xae,0x08, /*b*/ 20 0xba,0x78,0x25,0x2e,0x1c,0xa6,0xb4,0xc6,0xe8,0xdd,0x74,0x1f,0x4b,0xbd,0x8b,0x8a, /*c*/ 21 0x70,0x3e,0xb5,0x66,0x48,0x03,0xf6,0x0e,0x61,0x35,0x57,0xb9,0x86,0xc1,0x1d,0x9e, /*d*/ 22 0xe1,0xf8,0x98,0x11,0x69,0xd9,0x8e,0x94,0x9b,0x1e,0x87,0xe9,0xce,0x55,0x28,0xdf, /*e*/ 23 0x8c,0xa1,0x89,0x0d,0xbf,0xe6,0x42,0x68,0x41,0x99,0x2d,0x0f,0xb0,0x54,0xbb,0x16 /*f*/ 24 }; 25 unsigned char invsBox[256] = 26 { /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ 27 0x52,0x09,0x6a,0xd5,0x30,0x36,0xa5,0x38,0xbf,0x40,0xa3,0x9e,0x81,0xf3,0xd7,0xfb, /*0*/ 28 0x7c,0xe3,0x39,0x82,0x9b,0x2f,0xff,0x87,0x34,0x8e,0x43,0x44,0xc4,0xde,0xe9,0xcb, /*1*/ 29 0x54,0x7b,0x94,0x32,0xa6,0xc2,0x23,0x3d,0xee,0x4c,0x95,0x0b,0x42,0xfa,0xc3,0x4e, /*2*/ 30 0x08,0x2e,0xa1,0x66,0x28,0xd9,0x24,0xb2,0x76,0x5b,0xa2,0x49,0x6d,0x8b,0xd1,0x25, /*3*/ 31 0x72,0xf8,0xf6,0x64,0x86,0x68,0x98,0x16,0xd4,0xa4,0x5c,0xcc,0x5d,0x65,0xb6,0x92, /*4*/ 32 0x6c,0x70,0x48,0x50,0xfd,0xed,0xb9,0xda,0x5e,0x15,0x46,0x57,0xa7,0x8d,0x9d,0x84, /*5*/ 33 0x90,0xd8,0xab,0x00,0x8c,0xbc,0xd3,0x0a,0xf7,0xe4,0x58,0x05,0xb8,0xb3,0x45,0x06, /*6*/ 34 0xd0,0x2c,0x1e,0x8f,0xca,0x3f,0x0f,0x02,0xc1,0xaf,0xbd,0x03,0x01,0x13,0x8a,0x6b, /*7*/ 35 0x3a,0x91,0x11,0x41,0x4f,0x67,0xdc,0xea,0x97,0xf2,0xcf,0xce,0xf0,0xb4,0xe6,0x73, /*8*/ 36 0x96,0xac,0x74,0x22,0xe7,0xad,0x35,0x85,0xe2,0xf9,0x37,0xe8,0x1c,0x75,0xdf,0x6e, /*9*/ 37 0x47,0xf1,0x1a,0x71,0x1d,0x29,0xc5,0x89,0x6f,0xb7,0x62,0x0e,0xaa,0x18,0xbe,0x1b, /*a*/ 38 0xfc,0x56,0x3e,0x4b,0xc6,0xd2,0x79,0x20,0x9a,0xdb,0xc0,0xfe,0x78,0xcd,0x5a,0xf4, /*b*/ 39 0x1f,0xdd,0xa8,0x33,0x88,0x07,0xc7,0x31,0xb1,0x12,0x10,0x59,0x27,0x80,0xec,0x5f, /*c*/ 40 0x60,0x51,0x7f,0xa9,0x19,0xb5,0x4a,0x0d,0x2d,0xe5,0x7a,0x9f,0x93,0xc9,0x9c,0xef, /*d*/ 41 0xa0,0xe0,0x3b,0x4d,0xae,0x2a,0xf5,0xb0,0xc8,0xeb,0xbb,0x3c,0x83,0x53,0x99,0x61, /*e*/ 42 0x17,0x2b,0x04,0x7e,0xba,0x77,0xd6,0x26,0xe1,0x69,0x14,0x63,0x55,0x21,0x0c,0x7d /*f*/ 43 }; 44 memcpy(Sbox, sBox, 256); 45 memcpy(InvSbox, invsBox, 256); 46 KeyExpansion(key, w); 47 } 48 49 AES::~AES() 50 { 51 52 } 53 54 unsigned char* AES::Cipher(unsigned char* input) 55 { 56 unsigned char state[4][4]; 57 int i,r,c; 58 59 for(r=0; r<4; r++) 60 { 61 for(c=0; c<4 ;c++) 62 { 63 state[r][c] = input[c*4+r]; 64 } 65 } 66 67 AddRoundKey(state,w[0]); 68 69 for(i=1; i<=10; i++) 70 { 71 SubBytes(state); 72 ShiftRows(state); 73 if(i!=10)MixColumns(state); 74 AddRoundKey(state,w[i]); 75 } 76 77 for(r=0; r<4; r++) 78 { 79 for(c=0; c<4 ;c++) 80 { 81 input[c*4+r] = state[r][c]; 82 } 83 } 84 85 return input; 86 } 87 88 unsigned char* AES::InvCipher(unsigned char* input) 89 { 90 unsigned char state[4][4]; 91 int i,r,c; 92 93 for(r=0; r<4; r++) 94 { 95 for(c=0; c<4 ;c++) 96 { 97 state[r][c] = input[c*4+r]; 98 } 99 } 100 101 AddRoundKey(state, w[10]); 102 for(i=9; i>=0; i--) 103 { 104 InvShiftRows(state); 105 InvSubBytes(state); 106 AddRoundKey(state, w[i]); 107 if(i) 108 { 109 InvMixColumns(state); 110 } 111 } 112 113 for(r=0; r<4; r++) 114 { 115 for(c=0; c<4 ;c++) 116 { 117 input[c*4+r] = state[r][c]; 118 } 119 } 120 121 return input; 122 } 123 124 void* AES::Cipher(void* input, int length) 125 { 126 unsigned char* in = (unsigned char*) input; 127 int i; 128 if(!length) // 如果是0则当做字符串处理 129 { 130 while(*(in+length++)); 131 in = (unsigned char*) input; 132 } 133 for(i=0; i<length; i+=16) 134 { 135 Cipher(in+i); 136 } 137 return input; 138 } 139 140 void* AES::InvCipher(void* input, int length) 141 { 142 unsigned char* in = (unsigned char*) input; 143 int i; 144 for(i=0; i<length; i+=16) 145 { 146 InvCipher(in+i); 147 } 148 return input; 149 } 150 151 void AES::KeyExpansion(unsigned char* key, unsigned char w[][4][4]) 152 { 153 int i,j,r,c; 154 unsigned char rc[] = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36}; 155 for(r=0; r<4; r++) 156 { 157 for(c=0; c<4; c++) 158 { 159 w[0][r][c] = key[r+c*4]; 160 } 161 } 162 for(i=1; i<=10; i++) 163 { 164 for(j=0; j<4; j++) 165 { 166 unsigned char t[4]; 167 for(r=0; r<4; r++) 168 { 169 t[r] = j ? w[i][r][j-1] : w[i-1][r][3]; 170 } 171 if(j == 0) 172 { 173 unsigned char temp = t[0]; 174 for(r=0; r<3; r++) 175 { 176 t[r] = Sbox[t[(r+1)%4]]; 177 } 178 t[3] = Sbox[temp]; 179 t[0] ^= rc[i-1]; 180 } 181 for(r=0; r<4; r++) 182 { 183 w[i][r][j] = w[i-1][r][j] ^ t[r]; 184 } 185 } 186 } 187 } 188 189 unsigned char AES::FFmul(unsigned char a, unsigned char b) 190 { 191 unsigned char bw[4]; 192 unsigned char res=0; 193 int i; 194 bw[0] = b; 195 for(i=1; i<4; i++) 196 { 197 bw[i] = bw[i-1]<<1; 198 if(bw[i-1]&0x80) 199 { 200 bw[i]^=0x1b; 201 } 202 } 203 for(i=0; i<4; i++) 204 { 205 if((a>>i)&0x01) 206 { 207 res ^= bw[i]; 208 } 209 } 210 return res; 211 } 212 213 void AES::SubBytes(unsigned char state[][4]) 214 { 215 int r,c; 216 for(r=0; r<4; r++) 217 { 218 for(c=0; c<4; c++) 219 { 220 state[r][c] = Sbox[state[r][c]]; 221 } 222 } 223 } 224 225 void AES::ShiftRows(unsigned char state[][4]) 226 { 227 unsigned char t[4]; 228 int r,c; 229 for(r=1; r<4; r++) 230 { 231 for(c=0; c<4; c++) 232 { 233 t[c] = state[r][(c+r)%4]; 234 } 235 for(c=0; c<4; c++) 236 { 237 state[r][c] = t[c]; 238 } 239 } 240 } 241 242 void AES::MixColumns(unsigned char state[][4]) 243 { 244 unsigned char t[4]; 245 int r,c; 246 for(c=0; c< 4; c++) 247 { 248 for(r=0; r<4; r++) 249 { 250 t[r] = state[r][c]; 251 } 252 for(r=0; r<4; r++) 253 { 254 state[r][c] = FFmul(0x02, t[r]) 255 ^ FFmul(0x03, t[(r+1)%4]) 256 ^ FFmul(0x01, t[(r+2)%4]) 257 ^ FFmul(0x01, t[(r+3)%4]); 258 } 259 } 260 } 261 262 void AES::AddRoundKey(unsigned char state[][4], unsigned char k[][4]) 263 { 264 int r,c; 265 for(c=0; c<4; c++) 266 { 267 for(r=0; r<4; r++) 268 { 269 state[r][c] ^= k[r][c]; 270 } 271 } 272 } 273 274 void AES::InvSubBytes(unsigned char state[][4]) 275 { 276 int r,c; 277 for(r=0; r<4; r++) 278 { 279 for(c=0; c<4; c++) 280 { 281 state[r][c] = InvSbox[state[r][c]]; 282 } 283 } 284 } 285 286 void AES::InvShiftRows(unsigned char state[][4]) 287 { 288 unsigned char t[4]; 289 int r,c; 290 for(r=1; r<4; r++) 291 { 292 for(c=0; c<4; c++) 293 { 294 t[c] = state[r][(c-r+4)%4]; 295 } 296 for(c=0; c<4; c++) 297 { 298 state[r][c] = t[c]; 299 } 300 } 301 } 302 303 void AES::InvMixColumns(unsigned char state[][4]) 304 { 305 unsigned char t[4]; 306 int r,c; 307 for(c=0; c< 4; c++) 308 { 309 for(r=0; r<4; r++) 310 { 311 t[r] = state[r][c]; 312 } 313 for(r=0; r<4; r++) 314 { 315 state[r][c] = FFmul(0x0e, t[r]) 316 ^ FFmul(0x0b, t[(r+1)%4]) 317 ^ FFmul(0x0d, t[(r+2)%4]) 318 ^ FFmul(0x09, t[(r+3)%4]); 319 } 320 } 321 }
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,我封装了一个接口类,声明如下:
(3)aes_encryptor.h
#ifndef SRC_UTILS_AES_ENCRYPTOR_H #define SRC_UTILS_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 // SRC_UTILS_AES_ENCRYPTOR_H
(4)aes_encryptor.cpp
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
1 #include "aes.h" 2 #include "aes_encryptor.h" 3 #include "log.h" 4 5 #include <fstream> 6 using namespace std; 7 8 AesEncryptor::AesEncryptor(unsigned char* key) 9 { 10 m_pEncryptor = new AES(key); 11 } 12 13 14 AesEncryptor::~AesEncryptor(void) 15 { 16 delete m_pEncryptor; 17 } 18 19 void AesEncryptor::Byte2Hex(const unsigned char* src, int len, char* dest) { 20 for (int i=0; i<len; ++i) { 21 sprintf_s(dest + i * 2, 3, "%02X", src[i]); 22 } 23 } 24 25 void AesEncryptor::Hex2Byte(const char* src, int len, unsigned char* dest) { 26 int length = len / 2; 27 for (int i=0; i<length; ++i) { 28 dest[i] = Char2Int(src[i * 2]) * 16 + Char2Int(src[i * 2 + 1]); 29 } 30 } 31 32 int AesEncryptor::Char2Int(char c) { 33 if ('0' <= c && c <= '9') { 34 return (c - '0'); 35 } 36 else if ('a' <= c && c<= 'f') { 37 return (c - 'a' + 10); 38 } 39 else if ('A' <= c && c<= 'F') { 40 return (c - 'A' + 10); 41 } 42 return -1; 43 } 44 45 string AesEncryptor::EncryptString(string strInfor) { 46 int nLength = strInfor.length(); 47 int spaceLength = 16 - (nLength % 16); 48 unsigned char* pBuffer = new unsigned char[nLength + spaceLength]; 49 memset(pBuffer, '\0', nLength + spaceLength); 50 memcpy_s(pBuffer, nLength + spaceLength, strInfor.c_str(), nLength); 51 m_pEncryptor->Cipher(pBuffer, nLength + spaceLength); 52 53 // 这里需要把得到的字符数组转换成十六进制字符串 54 char* pOut = new char[2 * (nLength + spaceLength)]; 55 memset(pOut, '\0', 2 * (nLength + spaceLength)); 56 Byte2Hex(pBuffer, nLength + spaceLength, pOut); 57 58 string retValue(pOut); 59 delete[] pBuffer; 60 delete[] pOut; 61 return retValue; 62 } 63 64 string AesEncryptor::DecryptString(string strMessage) { 65 int nLength = strMessage.length() / 2; 66 unsigned char* pBuffer = new unsigned char[nLength]; 67 memset(pBuffer, '\0', nLength); 68 Hex2Byte(strMessage.c_str(), strMessage.length(), pBuffer); 69 70 m_pEncryptor->InvCipher(pBuffer, nLength); 71 string retValue((char*)pBuffer); 72 delete[] pBuffer; 73 return retValue; 74 } 75 76 void AesEncryptor::EncryptTxtFile(const char* inputFileName, const char* outputFileName) { 77 ifstream ifs; 78 79 // Open file: 80 ifs.open(inputFileName); 81 if (!ifs) { 82 UNILOGW("AesEncryptor::EncryptTxtFile() - Open input file failed!"); 83 return ; 84 } 85 86 // Read config data: 87 string strInfor; 88 string strLine; 89 while (!ifs.eof()) { 90 char temp[1024]; 91 memset(temp, '\0', 1024); 92 ifs.read(temp, 1000); 93 strInfor += temp; 94 } 95 ifs.close(); 96 97 // Encrypt 98 strLine = EncryptString(strInfor); 99 100 // Writefile 101 ofstream ofs; 102 ofs.open(outputFileName); 103 if (!ofs) { 104 UNILOGW("AesEncryptor::EncryptTxtFile() - Open output file failed!"); 105 return ; 106 } 107 ofs << strLine; 108 ofs.close(); 109 } 110 111 void AesEncryptor::DecryptTxtFile(const char* inputFile, const char* outputFile) { 112 ifstream ifs; 113 114 // Open file: 115 ifs.open(inputFile); 116 if (!ifs) { 117 UNILOGW("AesEncryptor::DecryptTxtFile() - Open input file failed!"); 118 return ; 119 } 120 121 // Read config data: 122 string strInfor; 123 string strLine; 124 while (!ifs.eof()) { 125 char temp[1024]; 126 memset(temp, '\0', 1024); 127 ifs.read(temp, 1000); 128 strInfor += temp; 129 } 130 ifs.close(); 131 132 // Encrypt 133 strLine = DecryptString(strInfor); 134 135 // Writefile 136 ofstream ofs; 137 ofs.open(outputFile); 138 if (!ofs) { 139 UNILOGW("AesEncryptor::DecryptTxtFile() - Open output file failed!"); 140 return ; 141 } 142 ofs << strLine; 143 ofs.close(); 144 }
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。
PS: 多说一句,从网上看别人封装的代码时,先看评论和反应,有的时候网友写个带漏洞的程序坑死人不负责的。