使用C语言获取字符串或文件的MD5值

libmd5地址：https://sourceforge.net/projects/libmd5-rfc/

MD5Demo1.c

#include <stdio.h>
#include <string.h>
#include "md5/md5.h"
int main()
{
    const md5_byte_t *data = "All is well!";
    md5_byte_t digest[16];
    md5_state_t md5StateT;
    md5_init(&md5StateT);
    md5_append(&md5StateT, data, strlen(data));
    md5_finish(&md5StateT, digest);
    char md5String[33] = { '' }, hexBuffer[3];
    for (size_t i = 0; i != 16; ++i)
    {
        if (digest[i] < 16)
            sprintf(hexBuffer, "0%X", digest[i]);
        else
            sprintf(hexBuffer, "%X", digest[i]);
        strcat(md5String, hexBuffer);
    }
    printf("%s
", md5String);
    system("pause");
    return 0;
}

MD5Demo2.c

#include <stdio.h>
#include <string.h>
#include <time.h>
#include "md5/md5.h"
#define INPUT_BUFFER_SIZE 100 * 1024
int main()
{
    const char *filename = "E:/Packages/Win7/en_windows_7_ultimate_with_sp1_x64_dvd_u_677332.iso";
    FILE *file = fopen(filename, "rb");
    if (file)
    {
        printf("正在计算MD5值...
");
        time_t startTime = time(NULL);
        md5_state_t md5StateT;
        md5_init(&md5StateT);
        char buffer[INPUT_BUFFER_SIZE];
        while (!feof(file))
        {
            size_t numberOfObjects = fread(buffer, sizeof(char), INPUT_BUFFER_SIZE, file);
            md5_append(&md5StateT, buffer, numberOfObjects);
        }
        md5_byte_t digest[16];
        md5_finish(&md5StateT, digest);
        char md5String[33] = { '' }, hexBuffer[3];
        for (size_t i = 0; i != 16; ++i)
        {
            if (digest[i] < 16)
                sprintf(hexBuffer, "0%x", digest[i]);
            else
                sprintf(hexBuffer, "%x", digest[i]);
            strcat(md5String, hexBuffer);
        }
        time_t endTime = time(NULL);
        fclose(file);
        printf("计算完毕：%s，耗时%u秒
", md5String, endTime - startTime);
    }
    else
        printf("无法打开文件：%s
", filename);
    system("pause");
    return 0;
}