C language implementation of MD5 Functions

It is transferred from http://witmax.cn/c-md5-code.html. The author is also on the Internet, but it is not clearly indicated.

The MD5 function code found on the Internet. After trying it, you can use it and record it. Contains three files, as follows:

Header file md5.h

#ifndef MD5_H#define MD5_Htypedef struct{unsigned int count[2];unsigned int state[4];unsigned char buffer[64];   }MD5_CTX;#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))#define ROTATE_LEFT(x,n) ((x << n) | (x >> (32-n)))#define FF(a,b,c,d,x,s,ac) \{ \a += F(b,c,d) + x + ac; \a = ROTATE_LEFT(a,s); \a += b; \}#define GG(a,b,c,d,x,s,ac) \{ \a += G(b,c,d) + x + ac; \a = ROTATE_LEFT(a,s); \a += b; \}#define HH(a,b,c,d,x,s,ac) \{ \a += H(b,c,d) + x + ac; \a = ROTATE_LEFT(a,s); \a += b; \}#define II(a,b,c,d,x,s,ac) \{ \a += I(b,c,d) + x + ac; \a = ROTATE_LEFT(a,s); \a += b; \}                                            void MD5Init(MD5_CTX *context);void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen);void MD5Final(MD5_CTX *context,unsigned char digest[16]);void MD5Transform(unsigned int state[4],unsigned char block[64]);void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len);void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len);#endif

C language file md5.c

#include <memory.h>#include "md5.h"unsigned char PADDING[]={0x80,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};void MD5Init(MD5_CTX *context){context->count[0] = 0;context->count[1] = 0;context->state[0] = 0x67452301;context->state[1] = 0xEFCDAB89;context->state[2] = 0x98BADCFE;context->state[3] = 0x10325476;}void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen){unsigned int i = 0,index = 0,partlen = 0;index = (context->count[0] >> 3) & 0x3F;partlen = 64 - index;context->count[0] += inputlen << 3;if(context->count[0] < (inputlen << 3))context->count[1]++;context->count[1] += inputlen >> 29;if(inputlen >= partlen){memcpy(&context->buffer[index],input,partlen);MD5Transform(context->state,context->buffer);for(i = partlen;i+64 <= inputlen;i+=64)MD5Transform(context->state,&input[i]);index = 0;        }  else{i = 0;}memcpy(&context->buffer[index],&input[i],inputlen-i);}void MD5Final(MD5_CTX *context,unsigned char digest[16]){unsigned int index = 0,padlen = 0;unsigned char bits[8];index = (context->count[0] >> 3) & 0x3F;padlen = (index < 56)?(56-index):(120-index);MD5Encode(bits,context->count,8);MD5Update(context,PADDING,padlen);MD5Update(context,bits,8);MD5Encode(digest,context->state,16);}void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len){unsigned int i = 0,j = 0;while(j < len){output[j] = input[i] & 0xFF;  output[j+1] = (input[i] >> 8) & 0xFF;output[j+2] = (input[i] >> 16) & 0xFF;output[j+3] = (input[i] >> 24) & 0xFF;i++;j+=4;}}void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len){unsigned int i = 0,j = 0;while(j < len){output[i] = (input[j]) |(input[j+1] << 8) |(input[j+2] << 16) |(input[j+3] << 24);i++;j+=4; }}void MD5Transform(unsigned int state[4],unsigned char block[64]){unsigned int a = state[0];unsigned int b = state[1];unsigned int c = state[2];unsigned int d = state[3];unsigned int x[64];MD5Decode(x,block,64);FF(a, b, c, d, x[ 0], 7, 0xd76aa478); /* 1 */FF(d, a, b, c, x[ 1], 12, 0xe8c7b756); /* 2 */FF(c, d, a, b, x[ 2], 17, 0x242070db); /* 3 */FF(b, c, d, a, x[ 3], 22, 0xc1bdceee); /* 4 */FF(a, b, c, d, x[ 4], 7, 0xf57c0faf); /* 5 */FF(d, a, b, c, x[ 5], 12, 0x4787c62a); /* 6 */FF(c, d, a, b, x[ 6], 17, 0xa8304613); /* 7 */FF(b, c, d, a, x[ 7], 22, 0xfd469501); /* 8 */FF(a, b, c, d, x[ 8], 7, 0x698098d8); /* 9 */FF(d, a, b, c, x[ 9], 12, 0x8b44f7af); /* 10 */FF(c, d, a, b, x[10], 17, 0xffff5bb1); /* 11 */FF(b, c, d, a, x[11], 22, 0x895cd7be); /* 12 */FF(a, b, c, d, x[12], 7, 0x6b901122); /* 13 */FF(d, a, b, c, x[13], 12, 0xfd987193); /* 14 */FF(c, d, a, b, x[14], 17, 0xa679438e); /* 15 */FF(b, c, d, a, x[15], 22, 0x49b40821); /* 16 *//* Round 2 */GG(a, b, c, d, x[ 1], 5, 0xf61e2562); /* 17 */GG(d, a, b, c, x[ 6], 9, 0xc040b340); /* 18 */GG(c, d, a, b, x[11], 14, 0x265e5a51); /* 19 */GG(b, c, d, a, x[ 0], 20, 0xe9b6c7aa); /* 20 */GG(a, b, c, d, x[ 5], 5, 0xd62f105d); /* 21 */GG(d, a, b, c, x[10], 9,  0x2441453); /* 22 */GG(c, d, a, b, x[15], 14, 0xd8a1e681); /* 23 */GG(b, c, d, a, x[ 4], 20, 0xe7d3fbc8); /* 24 */GG(a, b, c, d, x[ 9], 5, 0x21e1cde6); /* 25 */GG(d, a, b, c, x[14], 9, 0xc33707d6); /* 26 */GG(c, d, a, b, x[ 3], 14, 0xf4d50d87); /* 27 */GG(b, c, d, a, x[ 8], 20, 0x455a14ed); /* 28 */GG(a, b, c, d, x[13], 5, 0xa9e3e905); /* 29 */GG(d, a, b, c, x[ 2], 9, 0xfcefa3f8); /* 30 */GG(c, d, a, b, x[ 7], 14, 0x676f02d9); /* 31 */GG(b, c, d, a, x[12], 20, 0x8d2a4c8a); /* 32 *//* Round 3 */HH(a, b, c, d, x[ 5], 4, 0xfffa3942); /* 33 */HH(d, a, b, c, x[ 8], 11, 0x8771f681); /* 34 */HH(c, d, a, b, x[11], 16, 0x6d9d6122); /* 35 */HH(b, c, d, a, x[14], 23, 0xfde5380c); /* 36 */HH(a, b, c, d, x[ 1], 4, 0xa4beea44); /* 37 */HH(d, a, b, c, x[ 4], 11, 0x4bdecfa9); /* 38 */HH(c, d, a, b, x[ 7], 16, 0xf6bb4b60); /* 39 */HH(b, c, d, a, x[10], 23, 0xbebfbc70); /* 40 */HH(a, b, c, d, x[13], 4, 0x289b7ec6); /* 41 */HH(d, a, b, c, x[ 0], 11, 0xeaa127fa); /* 42 */HH(c, d, a, b, x[ 3], 16, 0xd4ef3085); /* 43 */HH(b, c, d, a, x[ 6], 23,  0x4881d05); /* 44 */HH(a, b, c, d, x[ 9], 4, 0xd9d4d039); /* 45 */HH(d, a, b, c, x[12], 11, 0xe6db99e5); /* 46 */HH(c, d, a, b, x[15], 16, 0x1fa27cf8); /* 47 */HH(b, c, d, a, x[ 2], 23, 0xc4ac5665); /* 48 *//* Round 4 */II(a, b, c, d, x[ 0], 6, 0xf4292244); /* 49 */II(d, a, b, c, x[ 7], 10, 0x432aff97); /* 50 */II(c, d, a, b, x[14], 15, 0xab9423a7); /* 51 */II(b, c, d, a, x[ 5], 21, 0xfc93a039); /* 52 */II(a, b, c, d, x[12], 6, 0x655b59c3); /* 53 */II(d, a, b, c, x[ 3], 10, 0x8f0ccc92); /* 54 */II(c, d, a, b, x[10], 15, 0xffeff47d); /* 55 */II(b, c, d, a, x[ 1], 21, 0x85845dd1); /* 56 */II(a, b, c, d, x[ 8], 6, 0x6fa87e4f); /* 57 */II(d, a, b, c, x[15], 10, 0xfe2ce6e0); /* 58 */II(c, d, a, b, x[ 6], 15, 0xa3014314); /* 59 */II(b, c, d, a, x[13], 21, 0x4e0811a1); /* 60 */II(a, b, c, d, x[ 4], 6, 0xf7537e82); /* 61 */II(d, a, b, c, x[11], 10, 0xbd3af235); /* 62 */II(c, d, a, b, x[ 2], 15, 0x2ad7d2bb); /* 63 */II(b, c, d, a, x[ 9], 21, 0xeb86d391); /* 64 */state[0] += a;state[1] += b;state[2] += c;state[3] += d;}

MD5 function test code file

# Include <stdio. h> # include <stdlib. h> # include <string. h> # include "md5.h" int main (INT argc, char * argv []) {md5_ctx MD5; md5init (& MD5); int I; unsigned char encrypt [] = "admin"; // specify char decrypt [16]; md5update (& MD5, encrypt, strlen (char *) encrypt )); md5final (& MD5, decrypt); printf ("before encryption: % s \ n after encryption:", encrypt); for (I = 0; I <16; I ++) {printf ("% 02x", decrypt [I]);} getchar (); Return 0 ;}

Common MD5 encryption characters

7a57a5a743894a0e admin (16-bit MD5 lowercase encryption)
972130b75066c825 admin (16-bit MD5 capitalized encryption)
21232f297a57a5a743894a0e4a801fc3 admin (32-bit MD5 encrypted in lowercase)
73acd9a5972130b75066c82595a1fae3 admin (32-bit MD5 uppercase encryption)
49ba59abbe56e057 123456 (16-bit MD5 encrypted in lowercase)
E10adc3949ba59abbe56e057f20f883e 123456 (32-bit MD5 encrypted in lowercase)
469e80d32c0559f8 admin888 (16-bit MD5 lowercase encryption)
2299413865c28a35 admin888 (16-bit MD5 capitalized encryption)
7fef6171469e80d32c0559f88b377245 admin888 (32-bit MD5 encrypted in lowercase)
A1f63a962299413865c28a3593d359b0 admin888 (32-bit MD5 capitalized encryption)

PS. MD5 knowledge literacy

MD5: it is a specific algorithm, hash algorithm, Hasse algorithm, but non-encryption algorithm (because there is no key), which can be used for encryption (irreversible)
MD5 is a one-way hash function. The one-way hash function is used to hash a piece of data of any length into a fixed length. It is often used to generate message authentication codes. It can be used together with asymmetric algorithms for digital signatures.
Standard see http://www.ietf.org/rfc/rfc1321.txt
MD5 seems to have been cracked by a Chinese professor. By the way, I will give you an address at http://www.20.5.com/. it will be very convenient at some time .:)