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[];

    md5_state_t md5StateT;

    md5_init(&md5StateT);

    md5_append(&md5StateT, data, strlen(data));

    md5_finish(&md5StateT, digest);

    char md5String[] = { '\0' }, hexBuffer[];

    for (size_t i = ; i != ; ++i)

    {

        if (digest[i] < )

            sprintf(hexBuffer, "0%X", digest[i]);

        else

            sprintf(hexBuffer, "%X", digest[i]);

        strcat(md5String, hexBuffer);

    }

    printf("%s\n", md5String);

    system("pause");

    return ;

}

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...\n");

        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[];

        md5_finish(&md5StateT, digest);

        char md5String[] = { '\0' }, hexBuffer[];

        for (size_t i = ; i != ; ++i)

        {

            if (digest[i] < )

                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\n", md5String, endTime - startTime);

    }

    else

        printf("无法打开文件：%s\n", filename);

    system("pause");

    return ;

}