MD5信息摘要算法（Message Digest Algorithm）
- 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。
- 这里举例如何在16机器上实现md5算法：
- md5.h
md5.h1 #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 << 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.c
1 #include <string.h> 2 #include <stdio.h> 3 #include <math.h> 4 #include <stdlib.h> 5 #include <float.h> 6 #include <limits.h> 7 #include <ctype.h> 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 ========================
- 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.