整理出来的MD5算法的C++源代码

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本文介绍了一个基于C++的MD5加密类的实现细节，该类封装了MD5算法的标准过程，提供了文件、字符串及二进制数据的加密功能，并通过一个示例程序展示了如何使用这个类。

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下面的代码是从MD5标准的附录里面整理出来的，原来的是旧语法风格的C代码，现在我把它封装成了一个简单的C++类，以方便使用。有什么问题请回复。

#pragma once #include <iostream> #include <fstream> #include <memory> #include <boost/noncopyable.hpp> class CMD5 : boost::noncopyable { private: typedef unsigned char *POINTER; // POINTER defines a generic pointer type typedef unsigned short UINT2; // UINT2 defines a two byte word typedef unsigned long UINT4; // UINT4 defines a four byte word // Constants for MD5Transform routine. enum { S11 = 7, S12 = 12, S13 = 17, S14 = 22, S21 = 5, S22 = 9, S23 = 14, S24 = 20, S31 = 4, S32 = 11, S33 = 16, S34 = 23, S41 = 6, S42 = 10, S43 = 15, S44 = 21}; struct CMD5_CTX { UINT4 state[4]; // state (ABCD) UINT4 count[2]; // number of bits, modulo 2^64 (lsb first) unsigned char buffer[64]; // input buffer } m_Context; // md5 context unsigned char m_Digest[16]; // MD5 value const size_t m_nBufferSize; // buffer size for input file private: // Rotate x left to n bits UINT4 ROTATE_LEFT(UINT4 x, UINT4 n) const { return ((x << n) | (x >> (32 - n))); } // F, G, H and I are basic MD5 functions. UINT4 F(UINT4 x, UINT4 y, UINT4 z) const { return ((x & y) | (~x & z)); } UINT4 G(UINT4 x, UINT4 y, UINT4 z) const { return ((x & z) | (y & ~z)); } UINT4 H(UINT4 x, UINT4 y, UINT4 z) const { return (x ^ y ^ z); } UINT4 I(UINT4 x, UINT4 y, UINT4 z) const { return (y ^ (x | ~z)); } typedef UINT4 (CMD5::*pfBasicMd5)(UINT4, UINT4, UINT4) const; // transformations for rounds 1, 2, 3, and 4. // Rotation is separate from addition to prevent recomputation. void Func(pfBasicMd5 f, UINT4 &a, UINT4 b, UINT4 c, UINT4 d, UINT4 x, UINT4 s, UINT4 ac) const { a += (this->*f)(b, c, d) + x + ac; a = ROTATE_LEFT(a, s) + b; } private: // MD5 basic transformation. Transforms state based on block. void MD5Transform(UINT4 state[4], const unsigned char block[64]) const { UINT4 a = state[0]; UINT4 b = state[1]; UINT4 c = state[2]; UINT4 d = state[3]; UINT4 x[16] = {0}; Decode(x, block, 64); /* Round 1 */ Func(&CMD5::F, a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */ Func(&CMD5::F, d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */ Func(&CMD5::F, c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */ Func(&CMD5::F, b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */ Func(&CMD5::F, a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */ Func(&CMD5::F, d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */ Func(&CMD5::F, c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */ Func(&CMD5::F, b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */ Func(&CMD5::F, a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */ Func(&CMD5::F, d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */ Func(&CMD5::F, c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */ Func(&CMD5::F, b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */ Func(&CMD5::F, a, b, c, d, x[12], S11, 0x6b901122); /* 13 */ Func(&CMD5::F, d, a, b, c, x[13], S12, 0xfd987193); /* 14 */ Func(&CMD5::F, c, d, a, b, x[14], S13, 0xa679438e); /* 15 */ Func(&CMD5::F, b, c, d, a, x[15], S14, 0x49b40821); /* 16 */ /* Round 2 */ Func(&CMD5::G, a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */ Func(&CMD5::G, d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */ Func(&CMD5::G, c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */ Func(&CMD5::G, b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */ Func(&CMD5::G, a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */ Func(&CMD5::G, d, a, b, c, x[10], S22, 0x2441453); /* 22 */ Func(&CMD5::G, c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */ Func(&CMD5::G, b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */ Func(&CMD5::G, a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */ Func(&CMD5::G, d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */ Func(&CMD5::G, c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */ Func(&CMD5::G, b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */ Func(&CMD5::G, a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */ Func(&CMD5::G, d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */ Func(&CMD5::G, c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */ Func(&CMD5::G, b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */ /* Round 3 */ Func(&CMD5::H, a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */ Func(&CMD5::H, d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */ Func(&CMD5::H, c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */ Func(&CMD5::H, b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */ Func(&CMD5::H, a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */ Func(&CMD5::H, d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */ Func(&CMD5::H, c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */ Func(&CMD5::H, b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */ Func(&CMD5::H, a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */ Func(&CMD5::H, d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */ Func(&CMD5::H, c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */ Func(&CMD5::H, b, c, d, a, x[ 6], S34, 0x4881d05); /* 44 */ Func(&CMD5::H, a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */ Func(&CMD5::H, d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */ Func(&CMD5::H, c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */ Func(&CMD5::H, b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */ /* Round 4 */ Func(&CMD5::I, a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */ Func(&CMD5::I, d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */ Func(&CMD5::I, c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */ Func(&CMD5::I, b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */ Func(&CMD5::I, a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */ Func(&CMD5::I, d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */ Func(&CMD5::I, c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */ Func(&CMD5::I, b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */ Func(&CMD5::I, a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */ Func(&CMD5::I, d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */ Func(&CMD5::I, c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */ Func(&CMD5::I, b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */ Func(&CMD5::I, a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */ Func(&CMD5::I, d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */ Func(&CMD5::I, c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */ Func(&CMD5::I, b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */ state[0] += a; state[1] += b; state[2] += c; state[3] += d; // Zeroize sensitive information memset((POINTER)x, 0, sizeof(x)); } // Encodes input (UINT4) into output (unsigned char). Assumes len is a multiple of 4 void Encode(unsigned char *output, const UINT4 *input, size_t len) const { for (size_t i = 0, j = 0; j < len; i++, j += 4) { output[j + 0] = (unsigned char)((input[i] >> 0) & 0xff); output[j + 1] = (unsigned char)((input[i] >> 8) & 0xff); output[j + 2] = (unsigned char)((input[i] >> 16) & 0xff); output[j + 3] = (unsigned char)((input[i] >> 24) & 0xff); } } // Decodes input (unsigned char) into output (UINT4). Assumes len is a multiple of 4 void Decode(UINT4 *output, const unsigned char * input, size_t len) const { for (size_t i = 0, j = 0; j < len; i++, j += 4) { output[i] = (((UINT4)input[j+0]) << 0) | (((UINT4)input[j+1]) << 8) | (((UINT4)input[j+2]) << 16) | (((UINT4)input[j+3]) << 24); } } private: // MD5 initialization. Begins an MD5 operation, writing a new m_Context. void MD5Init() { memset(&m_Digest, 0, sizeof(m_Digest)); memset(&m_Context, 0, sizeof(m_Context)); m_Context.count[0] = 0; m_Context.count[1] = 0; m_Context.state[0] = 0x67452301; m_Context.state[1] = 0xefcdab89; m_Context.state[2] = 0x98badcfe; m_Context.state[3] = 0x10325476; } // MD5 block update operation. Continues an MD5 message-digest operation, // processing another message block, and updating the m_Context. void MD5Update (const unsigned char *input, unsigned int inputLen) { // Compute number of bytes mod 64 unsigned int index = (unsigned int)((m_Context.count[0] >> 3) & 0x3F); const unsigned int partLen = 64 - index; // Update number of bits if ((m_Context.count[0] += ((UINT4)inputLen << 3)) < ((UINT4)inputLen << 3)) { m_Context.count[1]++; } m_Context.count[1] += ((UINT4)inputLen >> 29); // Transform as many times as possible. unsigned int i = 0; if (inputLen >= partLen) { memcpy(&m_Context.buffer[index], input, partLen); MD5Transform(m_Context.state, m_Context.buffer); for (i = partLen; i + 63 < inputLen; i += 64) { MD5Transform(m_Context.state, &input[i]); } index = 0; } // Buffer remaining input memcpy((POINTER)&m_Context.buffer[index], (POINTER)&input[i], inputLen-i); } // MD5 finalization. Ends an MD5 message-digest operation, writing the // the message digest and zeroizing the m_Context. void MD5Final() { unsigned char bits[8] = {0}; // Save number of bits Encode(bits, m_Context.count, 8); // Pad out to 56 mod 64. */ const unsigned int index = (unsigned int)((m_Context.count[0] >> 3) & 0x3f); const unsigned int padLen = (index < 56) ? (56 - index) : (120 - index); const unsigned char padding[64] = {0x80, 0}; MD5Update(padding, padLen); MD5Update(bits, 8); // Append length (before padding) Encode(m_Digest, m_Context.state, 16); // Store state in digest memset(&m_Context, 0, sizeof(m_Context)); // Zeroize sensitive information. } public: CMD5(size_t nBufferSize = BUFSIZ) : m_nBufferSize(std::max<size_t>(BUFSIZ, nBufferSize)) { MD5Init(); } // Digests a file and return the result. std::string MD5File(const char *filename) { unsigned char buffer[BUFSIZ] = {0}; MD5Init(); for (std::ifstream ifs(filename, std::ios_base::binary); ifs; NULL) { ifs.read((char*)buffer, BUFSIZ); MD5Update(buffer, ifs.gcount()); } MD5Final(); return MD5Hex(); } // Digests a string and return the result. std::string MD5String(const char *string) { MD5Init(); MD5Update((const unsigned char *)string, strlen(string)); MD5Final(); return MD5Hex(); } // Digests a buffer and return the result. std::string MD5Binary(const void *buffer, size_t byteLen) { MD5Init(); MD5Update((const unsigned char *)buffer, byteLen); MD5Final(); return MD5Hex(); } // Format a message digest in hexadecimal. std::string MD5Hex() const { char buffer[16 * 2 + 1] = {0}; for (unsigned int i = 0; i < 16; i++) { sprintf_s(buffer + i * 2, 3, "%02x", m_Digest[i]); } return buffer; } };

使用例子如下：

#include "md5.h" #include <ctime> #include <string.h> #include <iostream> // Arguments: // -s string // -f filename int main(int, const char *argv[]) { CMD5 md5(10240); const clock_t start = clock(); const char *p = "abc"; if (argv[1][0] == '-' && argv[1][1] == 's') md5.MD5String(argv[2]); else if (argv[1][0] == '-' && argv[1][1] == 'f') md5.MD5File(argv[2]); else md5.MD5Binary(p, 3); const double ms = 1000.0 * (clock() - start) / CLOCKS_PER_SEC; std::cout << md5.MD5Hex().c_str() << std::endl; std::cout << ms << " ms/n"; return 0; }