开发笔记:md5信息摘要算法基于16位机器运行

1. md5是一种密码散列函数，可以生成128位(16字节）的散列值，用于确保信息传输完整一致。


2. 这里举例如何在16机器上实现md5算法：


3. md5.h 
   
   
   

   1 #ifndef MD5_H
   2 #define MD5_H
   3
   4 typedef struct
   5 {
   6 unsigned long count[2];
   7 unsigned long state[4];
   8 unsigned char buffer[64];
   9 }MD5_CTX;
   10
   11
   12 #define F(x,y,z) ((x & y) | (~x & z))
   13 #define G(x,y,z) ((x & z) | (y & ~z))
   14 #define H(x,y,z) (x^y^z)
   15 #define I(x,y,z) (y ^ (x | ~z))
   16 #define ROTATE_LEFT(x,n) ((x <> (32-n)))
   17 #define FF(a,b,c,d,x,s,ac) 18 { 19 a += F(b,c,d) + x + ac; 20 a = ROTATE_LEFT(a,s); 21 a += b; 22 }
   23 #define GG(a,b,c,d,x,s,ac) 24 { 25 a += G(b,c,d) + x + ac; 26 a = ROTATE_LEFT(a,s); 27 a += b; 28 }
   29 #define HH(a,b,c,d,x,s,ac) 30 { 31 a += H(b,c,d) + x + ac; 32 a = ROTATE_LEFT(a,s); 33 a += b; 34 }
   35 #define II(a,b,c,d,x,s,ac) 36 { 37 a += I(b,c,d) + x + ac; 38 a = ROTATE_LEFT(a,s); 39 a += b; 40 }
   41 void MD5Init(MD5_CTX *context);
   42 void MD5Update(MD5_CTX *context,unsigned char *input,unsigned long inputlen);
   43 void MD5Final(MD5_CTX *context,unsigned char digest[16]);
   44 void MD5Transform(unsigned long state[4],unsigned char block[64]);
   45 void MD5Encode(unsigned char *output,unsigned long *input,unsigned long len);
   46 void MD5Decode(unsigned long *output,unsigned char *input,unsigned long len);
   47 void md5_test(void);
   48
   49 #endif
   50
   51 //================ end of file =====================
   

   
   md5.h

    



4. 
   
   
   

   1 #include <string.h>
   2 #include
   3 #include
   4 #include
   5 #include <float.h>
   6 #include
   7 #include
   8 #include "md5.h"
   9
   10 unsigned char PADDING[]={0x80,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
   11 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
   12 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
   13 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
   14
   15 void MD5Init(MD5_CTX *context)
   16 {
   17 context->count[0] = 0;
   18 context->count[1] = 0;
   19 context->state[0] = 0x67452301;
   20 context->state[1] = 0xEFCDAB89;
   21 context->state[2] = 0x98BADCFE;
   22 context->state[3] = 0x10325476;
   23 }
   24 void MD5Update(MD5_CTX *context,unsigned char *input,unsigned long inputlen)
   25 {
   26 unsigned long i = 0,index = 0,partlen = 0;
   27 index = (context->count[0] >> 3) & 0x3F;
   28 partlen = 64 - index;
   29 context->count[0] += inputlen <<3;
   30 if(context->count[0] <(inputlen <<3))
   31 context->count[1]++;
   32 context->count[1] += inputlen >> 29;
   33
   34 if(inputlen >= partlen)
   35 {
   36 memcpy(&context->buffer[index],input,partlen);
   37 MD5Transform(context->state,context->buffer);
   38 for(i = partlen;i+64 <= inputlen;i+=64)
   39 MD5Transform(context->state,&input[i]);
   40 index = 0;
   41 }
   42 else
   43 {
   44 i = 0;
   45 }
   46 memcpy(&context->buffer[index],&input[i],inputlen-i);
   47 }
   48 void MD5Final(MD5_CTX *context,unsigned char digest[16])
   49 {
   50 unsigned long index = 0,padlen = 0;
   51 unsigned char bits[8];
   52 index = (context->count[0] >> 3) & 0x3F;
   53 padlen = (index <56)?(56-index):(120-index);
   54 MD5Encode(bits,context->count,8);
   55 MD5Update(context,PADDING,padlen);
   56 MD5Update(context,bits,8);
   57 MD5Encode(digest,context->state,16);
   58 }
   59 void MD5Encode(unsigned char *output,unsigned long *input,unsigned long len)
   60 {
   61 unsigned long i = 0,j = 0;
   62 while(j < len)
   63 {
   64 output[j] = input[i] & 0xFF;
   65 output[j+1] = (input[i] >> 8) & 0xFF;
   66 output[j+2] = (input[i] >> 16) & 0xFF;
   67 output[j+3] = (input[i] >> 24) & 0xFF;
   68 i++;
   69 j+=4;
   70 }
   71 }
   72 void MD5Decode(unsigned long *output,unsigned char *input,unsigned long len)
   73 {
   74 unsigned long i = 0,j = 0;
   75 while(j < len)
   76 {
   77 output[i] = (input[j]) |
   78 ((unsigned long)input[j+1] <<8) |
   79 ((unsigned long)input[j+2] <<16) |
   80 ((unsigned long)input[j+3] <<24);
   81 i++;
   82 j+=4;
   83 }
   84 }
   85 void MD5Transform(unsigned long state[4],unsigned char block[64])
   86 {
   87 unsigned long a = state[0];
   88 unsigned long b = state[1];
   89 unsigned long c = state[2];
   90 unsigned long d = state[3];
   91 unsigned long x[64];
   92 MD5Decode(x,block,64);
   93 FF(a, b, c, d, x[ 0], 7, 0xd76aa478); /* 1 */
   94 FF(d, a, b, c, x[ 1], 12, 0xe8c7b756); /* 2 */
   95 FF(c, d, a, b, x[ 2], 17, 0x242070db); /* 3 */
   96 FF(b, c, d, a, x[ 3], 22, 0xc1bdceee); /* 4 */
   97 FF(a, b, c, d, x[ 4], 7, 0xf57c0faf); /* 5 */
   98 FF(d, a, b, c, x[ 5], 12, 0x4787c62a); /* 6 */
   99 FF(c, d, a, b, x[ 6], 17, 0xa8304613); /* 7 */
   100 FF(b, c, d, a, x[ 7], 22, 0xfd469501); /* 8 */
   101 FF(a, b, c, d, x[ 8], 7, 0x698098d8); /* 9 */
   102 FF(d, a, b, c, x[ 9], 12, 0x8b44f7af); /* 10 */
   103 FF(c, d, a, b, x[10], 17, 0xffff5bb1); /* 11 */
   104 FF(b, c, d, a, x[11], 22, 0x895cd7be); /* 12 */
   105 FF(a, b, c, d, x[12], 7, 0x6b901122); /* 13 */
   106 FF(d, a, b, c, x[13], 12, 0xfd987193); /* 14 */
   107 FF(c, d, a, b, x[14], 17, 0xa679438e); /* 15 */
   108 FF(b, c, d, a, x[15], 22, 0x49b40821); /* 16 */
   109
   110 /* Round 2 */
   111 GG(a, b, c, d, x[ 1], 5, 0xf61e2562); /* 17 */
   112 GG(d, a, b, c, x[ 6], 9, 0xc040b340); /* 18 */
   113 GG(c, d, a, b, x[11], 14, 0x265e5a51); /* 19 */
   114 GG(b, c, d, a, x[ 0], 20, 0xe9b6c7aa); /* 20 */
   115 GG(a, b, c, d, x[ 5], 5, 0xd62f105d); /* 21 */
   116 GG(d, a, b, c, x[10], 9, 0x2441453); /* 22 */
   117 GG(c, d, a, b, x[15], 14, 0xd8a1e681); /* 23 */
   118 GG(b, c, d, a, x[ 4], 20, 0xe7d3fbc8); /* 24 */
   119 GG(a, b, c, d, x[ 9], 5, 0x21e1cde6); /* 25 */
   120 GG(d, a, b, c, x[14], 9, 0xc33707d6); /* 26 */
   121 GG(c, d, a, b, x[ 3], 14, 0xf4d50d87); /* 27 */
   122 GG(b, c, d, a, x[ 8], 20, 0x455a14ed); /* 28 */
   123 GG(a, b, c, d, x[13], 5, 0xa9e3e905); /* 29 */
   124 GG(d, a, b, c, x[ 2], 9, 0xfcefa3f8); /* 30 */
   125 GG(c, d, a, b, x[ 7], 14, 0x676f02d9); /* 31 */
   126 GG(b, c, d, a, x[12], 20, 0x8d2a4c8a); /* 32 */
   127
   128 /* Round 3 */
   129 HH(a, b, c, d, x[ 5], 4, 0xfffa3942); /* 33 */
   130 HH(d, a, b, c, x[ 8], 11, 0x8771f681); /* 34 */
   131 HH(c, d, a, b, x[11], 16, 0x6d9d6122); /* 35 */
   132 HH(b, c, d, a, x[14], 23, 0xfde5380c); /* 36 */
   133 HH(a, b, c, d, x[ 1], 4, 0xa4beea44); /* 37 */
   134 HH(d, a, b, c, x[ 4], 11, 0x4bdecfa9); /* 38 */
   135 HH(c, d, a, b, x[ 7], 16, 0xf6bb4b60); /* 39 */
   136 HH(b, c, d, a, x[10], 23, 0xbebfbc70); /* 40 */
   137 HH(a, b, c, d, x[13], 4, 0x289b7ec6); /* 41 */
   138 HH(d, a, b, c, x[ 0], 11, 0xeaa127fa); /* 42 */
   139 HH(c, d, a, b, x[ 3], 16, 0xd4ef3085); /* 43 */
   140 HH(b, c, d, a, x[ 6], 23, 0x4881d05); /* 44 */
   141 HH(a, b, c, d, x[ 9], 4, 0xd9d4d039); /* 45 */
   142 HH(d, a, b, c, x[12], 11, 0xe6db99e5); /* 46 */
   143 HH(c, d, a, b, x[15], 16, 0x1fa27cf8); /* 47 */
   144 HH(b, c, d, a, x[ 2], 23, 0xc4ac5665); /* 48 */
   145
   146 /* Round 4 */
   147 II(a, b, c, d, x[ 0], 6, 0xf4292244); /* 49 */
   148 II(d, a, b, c, x[ 7], 10, 0x432aff97); /* 50 */
   149 II(c, d, a, b, x[14], 15, 0xab9423a7); /* 51 */
   150 II(b, c, d, a, x[ 5], 21, 0xfc93a039); /* 52 */
   151 II(a, b, c, d, x[12], 6, 0x655b59c3); /* 53 */
   152 II(d, a, b, c, x[ 3], 10, 0x8f0ccc92); /* 54 */
   153 II(c, d, a, b, x[10], 15, 0xffeff47d); /* 55 */
   154 II(b, c, d, a, x[ 1], 21, 0x85845dd1); /* 56 */
   155 II(a, b, c, d, x[ 8], 6, 0x6fa87e4f); /* 57 */
   156 II(d, a, b, c, x[15], 10, 0xfe2ce6e0); /* 58 */
   157 II(c, d, a, b, x[ 6], 15, 0xa3014314); /* 59 */
   158 II(b, c, d, a, x[13], 21, 0x4e0811a1); /* 60 */
   159 II(a, b, c, d, x[ 4], 6, 0xf7537e82); /* 61 */
   160 II(d, a, b, c, x[11], 10, 0xbd3af235); /* 62 */
   161 II(c, d, a, b, x[ 2], 15, 0x2ad7d2bb); /* 63 */
   162 II(b, c, d, a, x[ 9], 21, 0xeb86d391); /* 64 */
   163 state[0] += a;
   164 state[1] += b;
   165 state[2] += c;
   166 state[3] += d;
   167 }
   168
   169
   170 unsigned char plaintext_bytes[]="admin";//after encoding: 21232f297a57a5a743894a0e4a801fc3
   171 unsigned char ciphertext_bytes[16];
   172 void md5_test(void)
   173 {
   174 //object define
   175 MD5_CTX my_md5;
   176 //init object
   177 MD5Init(&my_md5);
   178 //encoding
   179 MD5Update(&my_md5,plaintext_bytes,strlen((char*)plaintext_bytes));
   180 MD5Final(&my_md5,ciphertext_bytes);
   181
   182 }
   183
   184
   185
   186
   187 //==================== end of file ========================
   

   
   md5.c

    



5. 因为32位机器 unsigned int == 32bits 为16位机器 unsigned int == 16bits 所以需要将 unsigned int ---- unsigned long 转换.

谢谢。

end.