如何创建在C字符串的MD5哈希？ [英] How to create a md5 hash of a string in C?

问题描述

我已经发现了一些MD5 code，它包含以下原型...

我一直在试图找出我必须把我要散列的字符串，我需要调用什么功能，以及在哪里可以找到字符串一旦被散列。我很困惑与问候什么UINT32 BUF [4]和UINT32位[2]是在结构中。

 结构MD5Context {
    UINT32的buf [4];
    UINT32比特[2];
    在无符号的字符[64];
};/ *
 *启动MD5积累。设置位计数为0，缓冲到神秘
 *初始化常量。
 * /
无效MD5Init（结构MD5Context *上下文）;/ *
 *更新背景下，以反映另一个缓冲区满的串联
 *字节。
 * /
无效MD5Update（结构MD5Context *的背景下，unsigned char型常量* buf中，无符号LEN）;/ *
 *最终结束语 - 填充到64字节边界的位模式
 * 1 0 *（变位的64位计数，MSB优先）
 * /
无效MD5Final（unsigned char型消化[16]，结构MD5Context *上下文）;/ *
 * MD5算法的核心，这改变现有的MD5哈希
 *反映增加新的数据的16个长字。 MD5Update块
 *数据，并将其转换成字节为长字该例程。
 * /
空隙MD5Transform（UINT32的buf [4]，UINT32在常量[16]）;
 

解决方案

我不知道这个特殊的库，但我已经用非常类似的电话。所以这是我最好的猜测：

  unsigned char型消化[16];
为const char *字符串=Hello World的;
结构MD5Context语境;
MD5Init（安培;背景）;
MD5Update（安培，背景，字符串的strlen（字符串））;
MD5Final（消化，＆安培;背景）;
 

这会给你回重新散列presentation一个整数。然后，您可以，如果你想围绕把它作为一个字符串转成十六进制再presentation这一点。

 字符md5string [33];
的for（int i = 0; I＆LT; 16; ++ I）
    sprintf的（安培; md5string [我* 2]，％02X（无符号整数）摘要[I]）;
 

I've found some md5 code that consists of the following prototypes...

I've been trying to find out where I have to put the string I want to hash, what functions I need to call, and where to find the string once it has been hashed. I'm confused with regards to what the uint32 buf[4] and uint32 bits[2] are in the struct.

struct MD5Context {
    uint32 buf[4];
    uint32 bits[2];
    unsigned char in[64];
};

/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
void MD5Init(struct MD5Context *context);

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
void MD5Update(struct MD5Context *context, unsigned char const *buf, unsigned len);

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern 
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
void MD5Final(unsigned char digest[16], struct MD5Context *context);

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
void MD5Transform(uint32 buf[4], uint32 const in[16]);

解决方案

I don't know this particular library, but I've used very similar calls. So this is my best guess:

unsigned char digest[16];
const char* string = "Hello World";
struct MD5Context context;
MD5Init(&context);
MD5Update(&context, string, strlen(string));
MD5Final(digest, &context);

This will give you back an integer representation of the hash. You can then turn this into a hex representation if you want to pass it around as a string.

char md5string[33];
for(int i = 0; i < 16; ++i)
    sprintf(&md5string[i*2], "%02x", (unsigned int)digest[i]);

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