c語言實(shí)現(xiàn)MD5算法的項(xiàng)目實(shí)踐
MD5介紹
1。 一種單向加密算法,即對明文加密,而不能通過密文得到明文。對原數(shù)據(jù)的任何改動,哪怕是1字節(jié),得到的MD5值都有很大的區(qū)別??梢杂霉奖硎荆好芪?Md5_calc(原文數(shù)據(jù));
應(yīng)用場景
1.密碼認(rèn)證;
2.數(shù)據(jù)校驗(yàn):
代碼分析 (基于qt5.14.2)
md5.c
#include <string.h> #include "md5.h" #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 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); 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); FF(d, a, b, c, x[ 1], 12, 0xe8c7b756); FF(c, d, a, b, x[ 2], 17, 0x242070db); FF(b, c, d, a, x[ 3], 22, 0xc1bdceee); FF(a, b, c, d, x[ 4], 7, 0xf57c0faf); FF(d, a, b, c, x[ 5], 12, 0x4787c62a); FF(c, d, a, b, x[ 6], 17, 0xa8304613); FF(b, c, d, a, x[ 7], 22, 0xfd469501); FF(a, b, c, d, x[ 8], 7, 0x698098d8); FF(d, a, b, c, x[ 9], 12, 0x8b44f7af); FF(c, d, a, b, x[10], 17, 0xffff5bb1); FF(b, c, d, a, x[11], 22, 0x895cd7be); FF(a, b, c, d, x[12], 7, 0x6b901122); FF(d, a, b, c, x[13], 12, 0xfd987193); FF(c, d, a, b, x[14], 17, 0xa679438e); FF(b, c, d, a, x[15], 22, 0x49b40821); GG(a, b, c, d, x[ 1], 5, 0xf61e2562); GG(d, a, b, c, x[ 6], 9, 0xc040b340); GG(c, d, a, b, x[11], 14, 0x265e5a51); GG(b, c, d, a, x[ 0], 20, 0xe9b6c7aa); GG(a, b, c, d, x[ 5], 5, 0xd62f105d); GG(d, a, b, c, x[10], 9, 0x2441453); GG(c, d, a, b, x[15], 14, 0xd8a1e681); GG(b, c, d, a, x[ 4], 20, 0xe7d3fbc8); GG(a, b, c, d, x[ 9], 5, 0x21e1cde6); GG(d, a, b, c, x[14], 9, 0xc33707d6); GG(c, d, a, b, x[ 3], 14, 0xf4d50d87); GG(b, c, d, a, x[ 8], 20, 0x455a14ed); GG(a, b, c, d, x[13], 5, 0xa9e3e905); GG(d, a, b, c, x[ 2], 9, 0xfcefa3f8); GG(c, d, a, b, x[ 7], 14, 0x676f02d9); GG(b, c, d, a, x[12], 20, 0x8d2a4c8a); HH(a, b, c, d, x[ 5], 4, 0xfffa3942); HH(d, a, b, c, x[ 8], 11, 0x8771f681); HH(c, d, a, b, x[11], 16, 0x6d9d6122); HH(b, c, d, a, x[14], 23, 0xfde5380c); HH(a, b, c, d, x[ 1], 4, 0xa4beea44); HH(d, a, b, c, x[ 4], 11, 0x4bdecfa9); HH(c, d, a, b, x[ 7], 16, 0xf6bb4b60); HH(b, c, d, a, x[10], 23, 0xbebfbc70); HH(a, b, c, d, x[13], 4, 0x289b7ec6); HH(d, a, b, c, x[ 0], 11, 0xeaa127fa); HH(c, d, a, b, x[ 3], 16, 0xd4ef3085); HH(b, c, d, a, x[ 6], 23, 0x4881d05); HH(a, b, c, d, x[ 9], 4, 0xd9d4d039); HH(d, a, b, c, x[12], 11, 0xe6db99e5); HH(c, d, a, b, x[15], 16, 0x1fa27cf8); HH(b, c, d, a, x[ 2], 23, 0xc4ac5665); II(a, b, c, d, x[ 0], 6, 0xf4292244); II(d, a, b, c, x[ 7], 10, 0x432aff97); II(c, d, a, b, x[14], 15, 0xab9423a7); II(b, c, d, a, x[ 5], 21, 0xfc93a039); II(a, b, c, d, x[12], 6, 0x655b59c3); II(d, a, b, c, x[ 3], 10, 0x8f0ccc92); II(c, d, a, b, x[10], 15, 0xffeff47d); II(b, c, d, a, x[ 1], 21, 0x85845dd1); II(a, b, c, d, x[ 8], 6, 0x6fa87e4f); II(d, a, b, c, x[15], 10, 0xfe2ce6e0); II(c, d, a, b, x[ 6], 15, 0xa3014314); II(b, c, d, a, x[13], 21, 0x4e0811a1); II(a, b, c, d, x[ 4], 6, 0xf7537e82); II(d, a, b, c, x[11], 10, 0xbd3af235); II(c, d, a, b, x[ 2], 15, 0x2ad7d2bb); II(b, c, d, a, x[ 9], 21, 0xeb86d391); state[0] += a; state[1] += b; state[2] += c; state[3] += d; }
md5.h
#ifndef MD5_H #define MD5_H typedef struct { unsigned int count[2]; unsigned int state[4]; unsigned char buffer[64]; }MD5_CTX; 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]); #endif
main.c
#include <QCoreApplication> extern "C"{ //添加頭文件 #include "md5.h" } int main(int argc, char *argv[]) { QCoreApplication a(argc, argv); int i, n; bool isfile = false; unsigned char decrypt[16]; MD5_CTX md5; if(argc > 1 && strlen(argv[1]) == 2 && !memcmp(argv[1], "-f", 2)) { isfile = true; } if(argc == 1 || (argc == 2 && isfile)) { fprintf(stderr, "usage:\n %s -f file ...\n %s string ...\n", argv[0], argv[0]); return 1; } if(isfile) { FILE *fp; for(n=2; n<argc; n++) { fp = fopen(argv[n], "rb"); if(fp == NULL) { fprintf(stderr, "File %s not exists, errno = %d, error = %s\n", argv[n], errno, strerror(errno)); continue; } MD5Init(&md5); do { unsigned char encrypt[1024]; while(!feof(fp)) { MD5Update(&md5, encrypt, fread(encrypt, 1, sizeof(encrypt), fp)); } fclose(fp); } while(0); MD5Final(&md5, decrypt); for(i=0; i<16; i++) { printf("%02x", decrypt[i]); //02x前需要加上 % } printf(" %s\n", argv[n]); } } else { for(n=1; n<argc; n++) { MD5Init(&md5); MD5Update(&md5,(unsigned char*) argv[n], strlen(argv[n])); MD5Final(&md5, decrypt); for(i=0; i<16; i++) { printf("%02x", decrypt[i]); //02x前需要加上 % } printf(" %s\n", argv[n]); } } return a.exec(); }
測試記錄 源碼打包(windeployqt.exe工具),得到MD5.exe
運(yùn)行測試,創(chuàng)建一個test.txt文件,打開文件寫入:123,保存關(guān)閉,運(yùn)行如下測試命令:MD5.exe -f test.txt 得到密文:202cb962ac59075b964b07152d234b70
測試準(zhǔn)確性,利用在線工具,輸入:123得到相同的密文,驗(yàn)證成功。
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