c++如何实现base64算法"}（c++如何实现base64算法"}）

Base64用途

1.用于对SOHO级路由器（网关设备）管理员帐户密码的加密

2.流媒体网站对于播放的流媒体文件的路径的加密

3.迅雷等下载软件对下载链接地址的加密

Base64算法

Base64编码要求把3个8位字节（3*8=24）转化为4个6位的字节（4*6=24），之后在6位的前面补两个0，形成8位一个字节的形式。

c++如何实现base64算法"}（c++如何实现base64算法"}）

Base64类

函数：

1	`unsigned` `int` `CreateMatchingEncodingBuffer (unsigned` `int` `p_InputByteCount,` `char** p_ppEncodingBuffer);`

创建匹配于编码的缓存空间。参数：1输入字节数，2进行编码需要的缓存空间；返回值：缓存空间大小。

1	`unsigned` `int` `CreateMatchingDecodingBuffer (char* p_pInputBufferString,` `char** p_ppDecodingBuffer);`

创建匹配于解码的缓存空间。参数：1解码对象缓存，2进行解码需要的缓存空间；返回值：缓存空间大小。

1	`void` `EncodeBuffer (char* p_pInputBuffer, unsigned` `int` `p_InputBufferLength,` `char* p_pOutputBufferString);`

进行编码。参数：1明文，2明文长度，3密文输出。

1	`unsigned` `int` `DecodeBuffer (char* p_pInputBufferString,` `char* p_pOutputBuffer);`

进行解码。参数：1密文，2明文；返回值：明文长度

C++实现：

头文件：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 View Code /************************************************ * * * CBase64.h * * Base 64 de- and encoding class * * * * ============================================ * * * * This class was written on 28.05.2003 * * by Jan Raddatz [jan-raddatz@web.de] * * * * ============================================ * * * * Copyright (c) by Jan Raddatz * * This class was published @ codeguru.com * * 28.05.2003 * * * ************************************************/ #pragma once #include <afx.h> #include <stdlib.h> #include <math.h> #include <memory.h> const static unsigned int MAX_LINE_LENGTH = 76; const static char BASE64_ALPHABET [64] = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', // 0 - 9 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', // 10 - 19 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', // 20 - 29 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', // 30 - 39 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', // 40 - 49 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', // 50 - 59 '8', '9', '+', '/' // 60 - 63 }; const static char BASE64_DEALPHABET [128] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0 - 9 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 10 - 19 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 20 - 29 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 30 - 39 0, 0, 0, 62, 0, 0, 0, 63, 52, 53, // 40 - 49 54, 55, 56, 57, 58, 59, 60, 61, 0, 0, // 50 - 59 0, 61, 0, 0, 0, 0, 1, 2, 3, 4, // 60 - 69 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, // 70 - 79 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // 80 - 89 25, 0, 0, 0, 0, 0, 0, 26, 27, 28, // 90 - 99 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // 100 - 109 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, // 110 - 119 49, 50, 51, 0, 0, 0, 0, 0 // 120 - 127 }; enum { UNABLE_TO_OPEN_INPUT_FILE, UNABLE_TO_OPEN_OUTPUT_FILE, UNABLE_TO_CREATE_OUTPUTBUFFER }; class CBase64 { public: CBase64 (); unsigned int CalculateRecquiredEncodeOutputBufferSize (unsigned int p_InputByteCount); unsigned int CalculateRecquiredDecodeOutputBufferSize (char* p_pInputBufferString); void EncodeByteTriple (char* p_pInputBuffer, unsigned int InputCharacters, char* p_pOutputBuffer); unsigned int DecodeByteQuartet (char* p_pInputBuffer, char* p_pOutputBuffer); void EncodeBuffer (char* p_pInputBuffer, unsigned int p_InputBufferLength, char*p_pOutputBufferString); unsigned int DecodeBuffer (char* p_pInputBufferString, char* p_pOutputBuffer); unsigned int CreateMatchingEncodingBuffer (unsigned int p_InputByteCount, char** p_ppEncodingBuffer); unsigned int CreateMatchingDecodingBuffer (char* p_pInputBufferString, char** p_ppDecodingBuffer); unsigned int EncodeFile (char* p_pSourceFileName, char* p_pEncodedFileName); unsigned int DecodeFile (char* p_pSourceFileName, char* p_pDecodedFileName); };

cpp文件：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 View Code /************************************************ * * * CBase64.cpp * * Base 64 de- and encoding class * * * * ============================================ * * * * This class was written on 28.05.2003 * * by Jan Raddatz [jan-raddatz@web.de] * * * * ============================================ * * * * Copyright (c) by Jan Raddatz * * This class was published @ codeguru.com * * 28.05.2003 * * * ************************************************/ #include "stdafx.h" #include "CBase64.h" CBase64::CBase64 () { } unsigned int CBase64::CalculateRecquiredEncodeOutputBufferSize (unsigned int p_InputByteCount) { div_t result = div (p_InputByteCount, 3); unsigned int RecquiredBytes = 0; if (result.rem == 0) { // Number of encoded characters RecquiredBytes = result.quot * 4; // CRLF -> "\r\n" each 76 characters result = div (RecquiredBytes, 76); RecquiredBytes += result.quot * 2; // Terminating null for the Encoded String RecquiredBytes += 1; return RecquiredBytes; } else { // Number of encoded characters RecquiredBytes = result.quot * 4 + 4; // CRLF -> "\r\n" each 76 characters result = div (RecquiredBytes, 76); RecquiredBytes += result.quot * 2; // Terminating null for the Encoded String RecquiredBytes += 1; return RecquiredBytes; } } unsigned int CBase64::CalculateRecquiredDecodeOutputBufferSize (char* p_pInputBufferString) { unsigned int BufferLength = strlen (p_pInputBufferString); div_t result = div (BufferLength, 4); if (p_pInputBufferString [BufferLength - 1] != '=') { return result.quot * 3; } else { if (p_pInputBufferString [BufferLength - 2] == '=') { return result.quot * 3 - 2; } else { return result.quot * 3 - 1; } } } void CBase64::EncodeByteTriple (char* p_pInputBuffer, unsigned int InputCharacters, char* p_pOutputBuffer) { unsigned int mask = 0xfc000000; unsigned int buffer = 0; char* temp = (char*) &buffer; temp [3] = p_pInputBuffer [0]; if (InputCharacters > 1) temp [2] = p_pInputBuffer [1]; if (InputCharacters > 2) temp [1] = p_pInputBuffer [2]; switch (InputCharacters) { case 3: { p_pOutputBuffer [0] = BASE64_ALPHABET [(buffer & mask) >> 26]; buffer = buffer << 6; p_pOutputBuffer [1] = BASE64_ALPHABET [(buffer & mask) >> 26]; buffer = buffer << 6; p_pOutputBuffer [2] = BASE64_ALPHABET [(buffer & mask) >> 26]; buffer = buffer << 6; p_pOutputBuffer [3] = BASE64_ALPHABET [(buffer & mask) >> 26]; break; } case 2: { p_pOutputBuffer [0] = BASE64_ALPHABET [(buffer & mask) >> 26]; buffer = buffer << 6; p_pOutputBuffer [1] = BASE64_ALPHABET [(buffer & mask) >> 26]; buffer = buffer << 6; p_pOutputBuffer [2] = BASE64_ALPHABET [(buffer & mask) >> 26]; p_pOutputBuffer [3] = '='; break; } case 1: { p_pOutputBuffer [0] = BASE64_ALPHABET [(buffer & mask) >> 26]; buffer = buffer << 6; p_pOutputBuffer [1] = BASE64_ALPHABET [(buffer & mask) >> 26]; p_pOutputBuffer [2] = '='; p_pOutputBuffer [3] = '='; break; } } } unsigned int CBase64::DecodeByteQuartet (char* p_pInputBuffer, char* p_pOutputBuffer) { unsigned int buffer = 0; if (p_pInputBuffer[3] == '=') { if (p_pInputBuffer[2] == '=') { buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[0]]) << 6; buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[1]]) << 6; buffer = buffer << 14; char* temp = (char*) &buffer; p_pOutputBuffer [0] = temp [3]; return 1; } else { buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[0]]) << 6; buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[1]]) << 6; buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[2]]) << 6; buffer = buffer << 8; char* temp = (char*) &buffer; p_pOutputBuffer [0] = temp [3]; p_pOutputBuffer [1] = temp [2]; return 2; } } else { buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[0]]) << 6; buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[1]]) << 6; buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[2]]) << 6; buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[3]]) << 6; buffer = buffer << 2; char* temp = (char*) &buffer; p_pOutputBuffer [0] = temp [3]; p_pOutputBuffer [1] = temp [2]; p_pOutputBuffer [2] = temp [1]; return 3; } return -1; } void CBase64::EncodeBuffer(char* p_pInputBuffer, unsigned int p_InputBufferLength, char* p_pOutputBufferString) { unsigned int FinishedByteQuartetsPerLine = 0; unsigned int InputBufferIndex = 0; unsigned int OutputBufferIndex = 0; memset (p_pOutputBufferString, 0, CalculateRecquiredEncodeOutputBufferSize (p_InputBufferLength)); while (InputBufferIndex < p_InputBufferLength) { if (p_InputBufferLength - InputBufferIndex <= 2) { FinishedByteQuartetsPerLine ++; EncodeByteTriple (p_pInputBuffer + InputBufferIndex, p_InputBufferLength - InputBufferIndex, p_pOutputBufferString + OutputBufferIndex); break; } else { FinishedByteQuartetsPerLine++; EncodeByteTriple (p_pInputBuffer + InputBufferIndex, 3, p_pOutputBufferString + OutputBufferIndex); InputBufferIndex += 3; OutputBufferIndex += 4; } if (FinishedByteQuartetsPerLine == 19) { p_pOutputBufferString [OutputBufferIndex ] = '\r'; p_pOutputBufferString [OutputBufferIndex+1] = '\n'; p_pOutputBufferString += 2; FinishedByteQuartetsPerLine = 0; } } } unsigned int CBase64::DecodeBuffer (char* p_pInputBufferString, char* p_pOutputBuffer) { unsigned int InputBufferIndex = 0; unsigned int OutputBufferIndex = 0; unsigned int InputBufferLength = strlen (p_pInputBufferString); char ByteQuartet [4]; while (InputBufferIndex < InputBufferLength) { for (int i = 0; i < 4; i++) { ByteQuartet [i] = p_pInputBufferString [InputBufferIndex]; // Ignore all characters except the ones in BASE64_ALPHABET if ((ByteQuartet [i] >= 48 && ByteQuartet [i] <= 57) || (ByteQuartet [i] >= 65 && ByteQuartet [i] <= 90) || (ByteQuartet [i] >= 97 && ByteQuartet [i] <= 122) || ByteQuartet [i] == '+' || ByteQuartet [i] == '/' || ByteQuartet [i] == '=') { } else { // Invalid character i--; } InputBufferIndex++; } OutputBufferIndex += DecodeByteQuartet (ByteQuartet, p_pOutputBuffer + OutputBufferIndex); } // OutputBufferIndex gives us the next position of the next decoded character // inside our output buffer and thus represents the number of decoded characters // in our buffer. return OutputBufferIndex; } unsigned int CBase64::CreateMatchingEncodingBuffer (unsigned int p_InputByteCount, char** p_ppEncodingBuffer) { unsigned int Size = CalculateRecquiredEncodeOutputBufferSize (p_InputByteCount); (*p_ppEncodingBuffer) = (char*) malloc (Size); memset (*p_ppEncodingBuffer, 0, Size); return Size; } unsigned int CBase64::CreateMatchingDecodingBuffer (char* p_pInputBufferString, char** p_ppDecodingBuffer) { unsigned int Size = CalculateRecquiredDecodeOutputBufferSize (p_pInputBufferString); (*p_ppDecodingBuffer) = (char*) malloc (Size+1); memset (*p_ppDecodingBuffer, 0, Size+1); return Size+1; } unsigned int CBase64::EncodeFile (char* p_pSourceFileName, char* p_pEncodedFileName) { CFile InputFile; CFile OutputFile; if (!InputFile.Open (p_pSourceFileName, CFile::modeRead)) return UNABLE_TO_OPEN_INPUT_FILE; if (!OutputFile.Open (p_pEncodedFileName, CFile::modeCreate|CFile::modeWrite)) return UNABLE_TO_OPEN_OUTPUT_FILE; char InputBuffer [19 * 3]; char* pOutputBuffer; CreateMatchingEncodingBuffer (sizeof (InputBuffer), &pOutputBuffer); if (pOutputBuffer == 0) return UNABLE_TO_CREATE_OUTPUTBUFFER; unsigned int ReadBytes = 0; while ((ReadBytes = InputFile.Read (InputBuffer, sizeof (InputBuffer))) != 0) { EncodeBuffer (InputBuffer, ReadBytes, pOutputBuffer); OutputFile.Write (pOutputBuffer, strlen (pOutputBuffer)); } OutputFile.Flush (); OutputFile.Close (); InputFile.Close (); return 0; } unsigned int CBase64::DecodeFile (char* p_pSourceFileName, char* p_pDecodedFileName) { CStdioFile InputFile; CFile OutputFile; if (!InputFile.Open (p_pSourceFileName, CFile::modeRead)) return UNABLE_TO_OPEN_INPUT_FILE; if (!OutputFile.Open (p_pDecodedFileName, CFile::modeCreate|CFile::modeWrite)) return UNABLE_TO_OPEN_OUTPUT_FILE; CString InputBuffer; char OutputBuffer[64]; unsigned int ReadBytes = 0; while ((ReadBytes = InputFile.ReadString (InputBuffer)) != 0) { InputBuffer.Remove ('\r'); InputBuffer.Remove ('\n'); unsigned int DecodedBytes = DecodeBuffer ((LPTSTR) (LPCTSTR) InputBuffer, OutputBuffer); OutputFile.Write (&OutputBuffer [0], DecodedBytes); } OutputFile.Flush (); OutputFile.Close (); InputFile.Close (); return 0; }