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密码知识系列之基于C++的MD5算法类

2013年06月11日 ⁄ 综合 ⁄ 共 8622字 ⁄ 字号 评论关闭

  MD5算法接收任意长的一个字符串,然后将它散列成128位的编码.它在各种加密,特别是消息摘要中用处非常的大

//"md5.h"

#ifndef _LGY_MD5_H
#define _LGY_MD5_H
 
/* MD5 Class. */
class MD5_CTX {
public:
     MD5_CTX();
     virtual ~MD5_CTX();
     void MD5Update ( unsignedchar *input, unsignedint inputLen);
     void MD5Final (unsignedchar digest[16]);
 
private:
     unsignedlongint state[4];                    /* state (ABCD) */
     unsignedlongint count[2];                       /* number of bits, modulo 2^64 (lsb first) */
     unsignedchar buffer[64];       /* input buffer */
     unsignedchar PADDING[64];      /* What? */
 
private:
     void MD5Init ();
     void MD5Transform (unsignedlongint state[4], unsignedchar block[64]);
     void MD5_memcpy (unsignedchar* output, unsignedchar* input,unsignedint len);
     void Encode (unsignedchar *output, unsignedlongint *input,unsignedint len);
     void Decode (unsignedlongint *output, unsignedchar *input, unsignedint len);
     void MD5_memset (unsignedchar* output,int value,unsignedint len);
};
 
#endif
 
//md5 cpp
 
#include"md5.h"
 
/* Constants for MD5Transform routine.
*/
#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21
 
/* F, G, H and I are basic MD5 functions.
*/
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))
 
/* ROTATE_LEFT rotates x left n bits.
*/
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
 
/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
Rotation is separate from addition to prevent recomputation.
*/
#define FF(a, b, c, d, x, s, ac) { /
     (a) += F ((b), (c), (d)) + (x) + (unsignedlongint)(ac); /
     (a) = ROTATE_LEFT ((a), (s)); /
     (a) += (b); /
     }
#define GG(a, b, c, d, x, s, ac) { /
     (a) += G ((b), (c), (d)) + (x) + (unsignedlongint)(ac); /
     (a) = ROTATE_LEFT ((a), (s)); /
     (a) += (b); /
     }
#define HH(a, b, c, d, x, s, ac) { /
     (a) += H ((b), (c), (d)) + (x) + (unsignedlongint)(ac); /
     (a) = ROTATE_LEFT ((a), (s)); /
     (a) += (b); /
     }
#define II(a, b, c, d, x, s, ac) { /
     (a) += I ((b), (c), (d)) + (x) + (unsignedlongint)(ac); /
     (a) = ROTATE_LEFT ((a), (s)); /
     (a) += (b); /
     }
 
 
/* MD5 initialization. Begins an MD5 operation, writing a new context.
*/
 
MD5_CTX::MD5_CTX()
{
     MD5Init ();
}
 
MD5_CTX::~MD5_CTX()
{
}
 
void MD5_CTX::MD5Init ()
{
     this->count[0] = this->count[1] = 0;
     /* Load magic initialization constants.*/
     /*this->state[0] = 0x67452301;
     this->state[1] = 0xefcdab89;
     this->state[2] = 0x98badcfe;
     this->state[3] = 0x10325476;*/
    this->state[0] = 0x01234567;
    this->state[1] = 0x89abcdef;
    this->state[2] = 0xfedcba98;
    this->state[3] = 0x76543210;
     /* Add by Liguangyi */
     MD5_memset(PADDING, 0, sizeof(PADDING));
     *PADDING=0x80;
}
 
/* MD5 block update operation. Continues an MD5 message-digest
operation, processing another message block, and updating the
context.
*/
void MD5_CTX::MD5Update (unsignedchar *input,unsignedint inputLen)
{
     unsignedint i, index, partLen;
    
     /* Compute number of bytes mod 64 */
     index = (unsignedint)((this->count[0] >> 3) & 0x3F);
    
     /* Update number of bits */
     if ((this->count[0] += ((unsignedlongint)inputLen << 3))
         < ((unsignedlongint)inputLen << 3))
         this->count[1]++;
     this->count[1] += ((unsignedlongint)inputLen >> 29);
    
     partLen = 64 - index;
    
     /* Transform as many times as possible.
     */
     if (inputLen >= partLen) {
         MD5_memcpy((unsignedchar*)&this->buffer[index],
              (unsignedchar*)input, partLen);
         MD5Transform (this->state, this->buffer);
        
         for (i = partLen; i + 63 < inputLen; i += 64)
              MD5Transform (this->state, &input[i]);
        
         index = 0;
     }
     else
         i = 0;
    
     /* Buffer remaining input */
     MD5_memcpy ((unsignedchar*)&this->buffer[index], (unsignedchar*)&input[i], inputLen-i);
}
 
/* MD5 finalization. Ends an MD5 message-digest operation, writing the
the message digest and zeroizing the context.
*/
void MD5_CTX::MD5Final (unsignedchar digest[16])
{
     unsignedchar bits[8];
     unsignedint index, padLen;
    
     /* Save number of bits */
     Encode (bits, this->count, 8);
    
     /* Pad out to 56 mod 64.
     */
     index = (unsignedint)((this->count[0] >> 3) & 0x3f);
     padLen = (index < 56) ? (56 - index) : (120 - index);
     MD5Update ( PADDING, padLen);
    
     /* Append length (before padding) */
     MD5Update (bits, 8);
     /* Store state in digest */
     Encode (digest, this->state, 16);
    
     /* Zeroize sensitive information.
     */
     MD5_memset ((unsignedchar*)this, 0, sizeof (*this));
     this->MD5Init();
}
 
/* MD5 basic transformation. Transforms state based on block.
*/
void MD5_CTX::MD5Transform (unsignedlongint state[4], unsignedchar block[64])
{
     unsignedlongint a = state[0], b = state[1], c = state[2], d = state[3], x[16];
    
     Decode (x, block, 64);
    
     /* Round 1 */
     FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
     FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
     FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
     FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
     FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
     FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
     FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
     FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
     FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
     FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
     FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
     FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
     FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
     FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
     FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
     FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */
    
     /* Round 2 */
     GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
     GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
     GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
     GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
     GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
     GG (d, a, b, c, x[10], S22, 0x2441453); /* 22 */
     GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
     GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
     GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
     GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
     GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
     GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
     GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
     GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
     GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
     GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */
    
     /* Round 3 */
     HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
     HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
     HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
     HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
     HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
     HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
     HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
     HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
     HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
     HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
     HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
     HH (b, c, d, a, x[ 6], S34, 0x4881d05); /* 44 */
     HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
     HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
     HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
     HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */
    
     /* Round 4 */
     II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
     II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
     II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
     II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
     II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
     II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
     II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
     II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
     II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
     II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
     II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
     II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
     II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
     II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
     II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
     II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */
    
     state[0] += a;
     state[1] += b;
     state[2] += c;
     state[3] += d;
    
     /* Zeroize sensitive information.
     */
     MD5_memset ((unsignedchar*)x, 0, sizeof (x));
}
 
/* Encodes input (unsigned long int) into output (unsigned char). Assumes len is
a multiple of 4.
*/
void MD5_CTX::Encode (unsignedchar *output, unsignedlongint *input,unsignedint len)
{
     unsignedint i, j;
    
     for (i = 0, j = 0; j < len; i++, j += 4) {
         output[j] = (unsignedchar)(input[i] & 0xff);
         output[j+1] = (unsignedchar)((input[i] >> 8) & 0xff);
         output[j+2] = (unsignedchar)((input[i] >> 16) & 0xff);
         output[j+3] = (unsignedchar)((input[i] >> 24) & 0xff);
     }
}
 
/* Decodes input (unsigned char) into output (unsigned long int). Assumes len is
a multiple of 4.
*/
void MD5_CTX::Decode (unsignedlongint *output, unsignedchar *input, unsignedint len)
{
     unsignedint i, j;
    
     for (i = 0, j = 0; j < len; i++, j += 4)
         output[i] = ((unsignedlongint)input[j]) | (((unsignedlongint)input[j+1]) << 8) |
         (((unsignedlongint)input[j+2]) << 16) | (((unsignedlongint)input[j+3]) << 24);
}
 
/* Note: Replace "for loop" with standard memcpy if possible.
*/
 
void MD5_CTX::MD5_memcpy (unsignedchar* output, unsignedchar* input,unsignedint len)
{
     unsignedint i;
    
     for (i = 0; i < len; i++)
         output[i] = input[i];
}
 
/* Note: Replace "for loop" with standard memset if possible.
*/
void MD5_CTX::MD5_memset (unsignedchar* output,int value,unsignedint len)
{
     unsignedint i;
    
     for (i = 0; i < len; i++)
         ((char *)output)[i] = (char)value;
}
 
 

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