怎样加密文件夹
各位好！
请问各位高手一个问题，我想为文件夹加密，在用户点击它时，会自动跳出一个密码对话框，在密码输入正确后方可进入此文件夹。
问题点数：100、回复次数：3Top
1 楼ckacka（/*小红帽*/ckacka();）回复于 2002-06-11 18:33:09 得分 0
可以用基于html的办法，不过具体的我也没有试过。Top
2 楼spidertan（灭蚊刀）回复于 2002-06-11 20:19:11 得分 0
这里是解密一个文件的一些代码，如果想了解更详细的信息，看EncryptFile()和DecryptFile()方法在MSDN帮助中
//--------------------------------------------------------------------
// In this and all other sample and example code,
// use the #define and #include statements listed
// under #includes and #defines.
#include <stdio.h>
#include <windows.h>
#include <wincrypt.h>
#define MY_ENCODING_TYPE (PKCS_7_ASN_ENCODING | X509_ASN_ENCODING)
#define KEYLENGTH 0x00800000
void HandleError(char *s);
//--------------------------------------------------------------------
// The following #define statements are also required.
#define ENCRYPT_ALGORITHM CALG_RC4
#define ENCRYPT_BLOCK_SIZE 8
//--------------------------------------------------------------------
// Declare the function DecryptFile. Code for the function follows
// main.
BOOL DecryptFile(
PCHAR szSource,
PCHAR szDestination,
PCHAR szPassword);
void main(void)
{
//--------------------------------------------------------------------
// Declare and initialize variables.
PCHAR szSource;
PCHAR szDestination;
PCHAR szPassword;
char response;
if(!(szSource=(char *)malloc(100)))
HandleError("Memory allocation failed.");
if(!(szDestination=(char *)malloc(100)))
HandleError("Memory allocation failed.");
if(!(szPassword=(char *)malloc(100)))
HandleError("Memory allocation failed.");
printf("Decrypt a file. \n\n");
printf("Enter the name of the file to be decrypted: ");
scanf("%s",szSource);
printf("Enter the name of the output file: ");
scanf("%s",szDestination);
printf("Was a password used to encrypt this file? ( y/n ) ");
getchar();
scanf("%c",&response);
if(response == 'y')
{
printf("Enter the password:");
scanf("%s",szPassword);
}
else
{
printf("The key will be generated without using a password. \n");
free(szPassword);
szPassword = NULL;
}
if(!DecryptFile(szSource, szDestination, szPassword))
{
printf("\nError decrypting file. \n");
}
else
{
printf("\nDecryption of file %s succeeded. \n", szSource);
printf("The decrypted file is %s .\n",szDestination);
}
} // End of main
//--------------------------------------------------------------------
// Define the function Decryptfile.
static BOOL DecryptFile(
PCHAR szSource,
PCHAR szDestination,
PCHAR szPassword)
{
//--------------------------------------------------------------------
// Declare and initialize local variables.
FILE *hSource;
FILE *hDestination;
HCRYPTPROV hCryptProv;
HCRYPTKEY hKey;
HCRYPTHASH hHash;
PBYTE pbKeyBlob = NULL;
DWORD dwKeyBlobLen;
PBYTE pbBuffer;
DWORD dwBlockLen;
DWORD dwBufferLen;
DWORD dwCount;
BOOL status = FALSE;
//--------------------------------------------------------------------
// Open source file.
if(!(hSource = fopen(szSource,"rb")))
{
HandleError("Error opening ciphertext file!");
}
//--------------------------------------------------------------------
// Open destination file.
if(!(hDestination = fopen(szDestination,"wb")))
{
HandleError("Error opening plaintext file!");
}
//--------------------------------------------------------------------
// Get a handle to the default provider.
if(!CryptAcquireContext(
&hCryptProv,
NULL,
MS_ENHANCED_PROV,
PROV_RSA_FULL,
0))
{
HandleError("Error during CryptAcquireContext!");
}
//--------------------------------------------------------------------
// Check for existence of a password.
if(!szPassword)
{
//--------------------------------------------------------------------
// Decrypt the file with the saved session key.
// Read key BLOB length from source file, and allocate memory.
fread(&dwKeyBlobLen, sizeof(DWORD), 1, hSource);
if(ferror(hSource) || feof(hSource))
{
HandleError("Error reading file header!");
}
if(!(pbKeyBlob = (BYTE *)malloc(dwKeyBlobLen)))
{
HandleError("Memory allocation error.");
}
//--------------------------------------------------------------------
// Read key BLOB from source file.
fread(pbKeyBlob, 1, dwKeyBlobLen, hSource);
if(ferror(hSource) || feof(hSource))
{
HandleError("Error reading file header!\n");
}
//--------------------------------------------------------------------
// Import key BLOB into CSP.
if(!CryptImportKey(
hCryptProv,
pbKeyBlob,
dwKeyBlobLen,
0,
0,
&hKey))
{
HandleError("Error during CryptImportKey!");
}
}
else
{
//--------------------------------------------------------------------
// Decrypt the file with a session key derived from a password.
Top
3 楼spidertan（灭蚊刀）回复于 2002-06-11 20:19:41 得分 100
//--------------------------------------------------------------------
// Create a hash object.
if(!CryptCreateHash(
hCryptProv,
CALG_MD5,
0,
0,
&hHash))
{
HandleError("Error during CryptCreateHash!");
}
//--------------------------------------------------------------------
// Hash in the password data.
if(!CryptHashData(
hHash,
(BYTE *)szPassword,
strlen(szPassword),
0))
{
HandleError("Error during CryptHashData!");
}
//--------------------------------------------------------------------
// Derive a session key from the hash object.
if(!CryptDeriveKey(
hCryptProv,
ENCRYPT_ALGORITHM,
hHash,
KEYLENGTH,
&hKey))
{
HandleError("Error during CryptDeriveKey!");
}
//--------------------------------------------------------------------
// Destroy the hash object.
CryptDestroyHash(hHash);
hHash = 0;
}
//--------------------------------------------------------------------
// The decryption key is now available, either having been imported
// from a BLOB read in from the source file or having been created
// using the password. This point in the program is not reached if
// the decryption key is not available.
//--------------------------------------------------------------------
// Determine the number of bytes to decrypt at a time.
// This must be a multiple of ENCRYPT_BLOCK_SIZE.
dwBlockLen = 1000 - 1000 % ENCRYPT_BLOCK_SIZE;
dwBufferLen = dwBlockLen;
//--------------------------------------------------------------------
// Allocate memory.
if(!(pbBuffer = (BYTE *)malloc(dwBufferLen)))
{
HandleError("Out of memory!\n");
}
//--------------------------------------------------------------------
// Decrypt source file, and write to destination file.
do {
//--------------------------------------------------------------------
// Read up to dwBlockLen bytes from source file.
dwCount = fread(
pbBuffer,
1,
dwBlockLen,
hSource);
if(ferror(hSource))
{
HandleError("Error reading ciphertext!");
}
//--------------------------------------------------------------------
// Decrypt data.
if(!CryptDecrypt(
hKey,
0,
feof(hSource),
0,
pbBuffer,
&dwCount))
{
HandleError("Error during CryptDecrypt!");
}
//--------------------------------------------------------------------
// Write data to destination file.
fwrite(
pbBuffer,
1,
dwCount,
hDestination);
if(ferror(hDestination))
{
HandleError("Error writing plaintext!");
}
}
while(!feof(hSource));
status = TRUE;
//--------------------------------------------------------------------
// Close files.
if(hSource)
fclose(hSource);
if(hDestination)
fclose(hDestination);
//--------------------------------------------------------------------
// Free memory.
if(pbKeyBlob)
free(pbKeyBlob);
if(pbBuffer)
free(pbBuffer);
//--------------------------------------------------------------------
// Destroy session key.
if(hKey)
CryptDestroyKey(hKey);
//--------------------------------------------------------------------
// Destroy hash object.
if(hHash)
CryptDestroyHash(hHash);
//--------------------------------------------------------------------
// Release provider handle.
if(hCryptProv)
CryptReleaseContext(hCryptProv, 0);
return status;
} // End of Decryptfile
//--------------------------------------------------------------------
// This example uses the function HandleError, a simple error
// handling function, to print an error message to the standard error
// (stderr) file and exit the program.
// For most applications, replace this function with one
// that does more extensive error reporting.
void HandleError(char *s)
{
fprintf(stderr,"An error occurred in running the program. \n");
fprintf(stderr,"%s\n",s);
fprintf(stderr, "Error number %x.\n", GetLastError());
fprintf(stderr, "Program terminating. \n");
exit(1);
} // End of HandleErrorTop
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