使用Windows提供dll实现MD5加密

#include <vcl.h>
#pragma hdrstop
#include <stdio.h>
#include <assert.h>
//---------------------------------------------------------------------------

#pragma argsused
typedef struct {
ULONG i[2]; /* number of _bits_ handled mod 2^64 */
ULONG buf[4]; /* scratch buffer */
unsigned char in[64]; /* input buffer */
unsigned char digest[16]; /* actual digest after MD5Final call */
} MD5_CTX;

#define MD5DIGESTLEN 16

#define PROTO_LIST(list) list

/*
* MTS: Each of these assumes MD5_CTX is locked against simultaneous use.
*/
typedef void (WINAPI* PMD5Init) PROTO_LIST ((MD5_CTX *));
typedef void (WINAPI* PMD5Update) PROTO_LIST ((MD5_CTX *, const unsigned char *, unsigned int));
typedef void (WINAPI* PMD5Final )PROTO_LIST ((MD5_CTX *));

PMD5Init MD5Init = NULL;
PMD5Update MD5Update = NULL;
PMD5Final MD5Final = NULL;

const char *Hex2ASC(const BYTE *Hex, int Len)
{
static char ASC[4096 * 2];
int i;

for (i = 0; i < Len; i++)
{
ASC[i * 2] = "0123456789ABCDEF"[Hex[i] >> 4];
ASC[i * 2 + 1] = "0123456789ABCDEF"[Hex[i] & 0x0F];
}
ASC[i * 2] = '\0';

return ASC;
}
int main(int argc, char* argv[])
{
MD5_CTX ctx;
unsigned char buf[10] = "123";
HINSTANCE hDLL;

if ( (hDLL = LoadLibrary("Cryptdll.dll")) > 0 )
{

MD5Init = (PMD5Init)GetProcAddress(hDLL,"MD5Init");
assert(MD5Init!=NULL);
MD5Update = (PMD5Update)GetProcAddress(hDLL,"MD5Update");
assert(MD5Update!=NULL);
MD5Final = (PMD5Final)GetProcAddress(hDLL,"MD5Final");
assert(MD5Final!=NULL);

MD5Init(&ctx);
MD5Update(&ctx,buf,8);
MD5Final(&ctx);

printf("%s \n",Hex2ASC(ctx.digest,16));

}
getchar();
return 0;
}