//プロジェクト名crypto001 C++ソースファイルcrypto001.cpp
#define _WIN32_WINNT 0x0500
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <windows.h>
extern "C" {
__declspec(dllexport) char * text_to_crypto(char * string01,char * string02,char * string03);
__declspec(dllexport) char * crypto_to_text(char * string01,char * string02,char * string03);
void base64_encode(int size,char* src, char* dst);
int base64_decode(char* src, char* dst);
static char* b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
//パスワード、平文_to_暗号文
char * text_to_crypto(char * string01,char * string02,char * string03)
{
	char *param,*param1;
	int n,len,done;
	done = FALSE;
	HCRYPTPROV hProv;
	HCRYPTHASH hHash;
	HCRYPTKEY hKey;
	len = strlen(string02);
	DWORD dwDataLen = len+1;
	param = (char *)calloc(1,len*2 + 1024);
	DWORD dwBufLen = len*2 + 1024;
	param = strcpy(param, string02);
	if(CryptAcquireContext(&hProv,NULL,MS_DEF_PROV,PROV_RSA_FULL,0))
		done = TRUE;
	else if(CryptAcquireContext(&hProv,NULL,MS_DEF_PROV,PROV_RSA_FULL,CRYPT_NEWKEYSET))
		done = TRUE;
	if (done)
	{
		done = FALSE;
		if(CryptCreateHash(hProv,CALG_MD5,0,0,&hHash))
		{
			if(CryptHashData(hHash,(BYTE*)string01,(DWORD)strlen(string01),0))
			{
				if(CryptDeriveKey(hProv,CALG_RC4,hHash,CRYPT_EXPORTABLE,&hKey))
				{
					if(CryptEncrypt(hKey,0,TRUE,0,(unsigned char *)param,&dwDataLen,dwBufLen))
					{
						done = TRUE;
					}
				}
			}
		}
	}
	if (done)
	{
		n=dwDataLen;
		param1 = (char *)calloc(1,n*2 + 1024);
		base64_encode(n,param,param1);
		len=strlen(string03);
		n=strlen(param1);
		if (len>=n+1)
		{
			memcpy(string03,param1,n);
			* (string03+n)='\0';
		}
		else
		{
			* string03='\0';
		}
	}
	else
	{
		* string03='\0';
	}
	free(param);
	free(param1);
	CryptReleaseContext(hProv, 0);
	CryptDestroyHash(hHash);
	CryptDestroyHash(hKey);
	return string03;
}
//パスワード、暗号文_to_平文
char * crypto_to_text(char * string01,char * string02,char * string03)
{
	char *param;
	int n,len,done;
	done = FALSE;
	HCRYPTPROV hProv;
	HCRYPTHASH hHash;
	HCRYPTKEY hKey;
	len = strlen(string02);
	param = (char *)calloc(1,len*2 + 1024);
	n=base64_decode(string02, param);
	DWORD dwDataLen = n;
	if(CryptAcquireContext(&hProv,NULL,MS_DEF_PROV,PROV_RSA_FULL,0))
		done = TRUE;
	else if(CryptAcquireContext(&hProv,NULL,MS_DEF_PROV,PROV_RSA_FULL,CRYPT_NEWKEYSET))
		done = TRUE;
	if (done)
	{
		done = FALSE;
		if(CryptCreateHash(hProv,CALG_MD5,0,0,&hHash))
		{
			if(CryptHashData(hHash,(BYTE*)string01,(DWORD)strlen(string01),0))
			{
				if(CryptDeriveKey(hProv,CALG_RC4,hHash,CRYPT_EXPORTABLE,&hKey))
				{
					if(CryptDecrypt(hKey,0,TRUE,0,(unsigned char *)param,&dwDataLen))
					{
						done = TRUE;
					}
				}
			}
		}
	}
	if (done)
	{
		len=strlen(string03);
		n=dwDataLen;
		if (len>=n+1)
		{
			memcpy(string03,param,n);
			* (string03+n)='\0';
		}
		else
		{
			* string03='\0';
		}
	}
	else
	{
		* string03='\0';
	}
	free(param);
	CryptReleaseContext(hProv, 0);
	CryptDestroyHash(hHash);
	CryptDestroyHash(hKey);
	return string03;
}
void base64_encode(int size,char* src, char* dst)
{
    int    i, j;
    int    cnt = 0;
    int    pos = 0;
    int    wk  = 0;
    char*  p   = dst;
    for(i=0 ; i<size ; i++)
    {
        wk <<= 8;
        wk |= (src[i] & 0xff);
        if( pos == 2 )    // 3byte
        {
            for(j=3 ; j>=0 ; j--)
            {
                *p = b64[(wk>>(6*j)) & 0x3f];
                p++;

                if( ++cnt == 76 )    // MIME
                {
                    *p  = '\r';    p++;
                    *p  = '\n';    p++;
                    cnt = 0;
                }
            }
            wk  = 0;
            pos = 0;
        }
        else
            pos++;
    }
    if( pos >= 1 )
    {
        for(i=0 ; i<(3-pos) ; i++)
            wk <<= 8;
        for(j=3 ; j>=0 ; j--)
        {
            if( (3-pos) <= j )
                *p = b64[(wk>>(6*j)) & 0x3f];
            else
                *p = '=';
            p++;
            if( ++cnt == 76 )
            {
                *p  = '\r';    p++;
                *p  = '\n';    p++;
                cnt = 0;
            }
        }
    }
    *p = '\0';
}
int base64_decode(char* src, char* dst)
{
	int	i, j; 
	int	n = 0;
	char   c;
	int	pos = 0;
	int	wk  = 0;
	char*  p   = dst;
	int end01=0;
	for(i=0 ; (unsigned)i<strlen(src) ; i++)
	{
		c = src[i];
		wk <<= 6;
		if( c >= 'A' && c <= 'Z' )
			wk |= (c - 'A') + 0;
		else if( c >= 'a' && c <= 'z' )
			wk |= (c - 'a') + 26;
		else if( c >= '0' && c <= '9' )
			wk |= (c - '0') + 52;
		else if( c == '+' )
			wk |= 62;
		else if( c == '/' )
			wk |= 63;
		else if( c == '=' )
		{
			wk |= 0;
			end01++;
		}
		else
		{
			wk >>= 6;
			continue;
		}
		if( pos == 3 )
		{
			if (end01==0)
			{
				for(j=2 ; j>=0 ; j--)
				{
					*p = (wk>>(j*8) & 0xff);
					p++;
					n++;
				}
			}
			if (end01==1)
			{
				for(j=2 ; j>=1 ; j--)
				{
					*p = (wk>>(j*8) & 0xff);
					p++;
					n++;
				}
			}
			if (end01==2)
			{
				for(j=2 ; j>=2 ; j--)
				{
					*p = (wk>>(j*8) & 0xff);
					p++;
					n++;
				}
			}
			wk  = 0;
			pos = 0;
		}
		else
			pos++;
	}
	if (pos==2)
	{
		for(i=0 ; i<(4-pos) ; i++)
		wk <<= 6;
		for(j=2 ; j>=2 ; j--)
		{
			*p = (wk>>(j*8) & 0xff);
			p++;
			n++;
		}
	}
	if (pos==3)
	{
		for(i=0 ; i<(4-pos) ; i++)
		wk <<= 6;
		for(j=2 ; j>=1 ; j--)
		{
			*p = (wk>>(j*8) & 0xff);
			p++;
			n++;
		}
	}
	*p = '\0';
	return n;
}
}