Просмотр

24.08.2004 16:31:57

И еще про экспорт.

Ответов: 1

Павел

Есть пример из MSDN:
=== code snippet start ===
//--------------------------------------------------------------------
// This example program creates a session key and a simple key
// BLOB holding that session key. The key BLOB can be written to disk
// and later read from a disk file.

#include <stdio.h>
#include <windows.h>
#include <wincrypt.h>
#include "WinCryptEx.h"

void MyHandleError(char *s);

int main(void)
{
//--------------------------------------------------------------------
// Declare and initialize variables.

HCRYPTPROV hProv; // CSP handle
HCRYPTKEY hSignKey; // Signature key pair handle
HCRYPTKEY hXchgKey; // Exchange key pair handle
HCRYPTKEY hKey; // Session key handle
BYTE *pbKeyBlob; // Pointer to a simple key BLOB
DWORD dwBlobLen; // The length of the key BLOB

//--------------------------------------------------------------------
// Acquire a cryptographic provider context handle.

if(CryptAcquireContext( &hProv,
"qqqq",
NULL,
71,
0))
{
printf("The CSP has been acquired. \n");
}
else
{
MyHandleError("Error during CryptAcquireContext.");
}

//--------------------------------------------------------------------
// Get a handle to the key exchange key.

if(CryptGetUserKey(
hProv,
AT_KEYEXCHANGE,
&hXchgKey))
{
printf("The key exchange key has been acquired. \n");
}
else
{
printf("Error during CryptGetUserKey exchange key.");
}
// hSignKey may be used to verify a signature. hXchgKey will be used
// to export a session key.

//--------------------------------------------------------------------
// Generate a session key.

if (CryptGenKey(
hProv,
CALG_G28147,
CRYPT_EXPORTABLE,
&hKey))
{
printf("Original session key is created. \n");
}
else
{
MyHandleError("ERROR -- CryptGenKey.");
}
// Determine the size of the key BLOB and allocate memory.

if(CryptExportKey(
hKey,
hXchgKey,
SIMPLEBLOB,
0,
NULL,
&dwBlobLen))
{
printf("Size of the BLOB for the session key determined. \n");
}
else
{
MyHandleError("Error computing BLOB length.");
}

if(pbKeyBlob = (BYTE*)malloc(dwBlobLen))
{
printf("Memory has been allocated for the BLOB. \n");
}
else
{
MyHandleError("Out of memory. \n");
}
//--------------------------------------------------------------------
// Export the key into a simple key BLOB.

if(CryptExportKey(
hKey,
hXchgKey,
SIMPLEBLOB,
0,
pbKeyBlob,
&dwBlobLen))
{
printf("Contents have been written to the BLOB. \n");
}
else
{
MyHandleError("Error during CryptExportKey.");
}
//--------------------------------------------------------------------
// At this point, other processing such as writing the key BLOB to
// a file could be done.

FILE *F = fopen("test.dat", "wb");
if (!F) return 11;
if (fwrite(pbKeyBlob, dwBlobLen, 1, F) != 1) return 12;
fclose(F);

//--------------------------------------------------------------------
// After all processing, clean up.

//--------------------------------------------------------------------
// Free the memory used by the key BLOB.

free(pbKeyBlob);

// Destroy the session key.
if(hKey)
CryptDestroyKey(hKey);

// Destroy the signature key handle.
if(hSignKey)
CryptDestroyKey(hSignKey);

// Destroy the key exchange key handle.
if(hXchgKey)
CryptDestroyKey(hXchgKey);

// Release the provider handle.
if(hProv)
CryptReleaseContext(hProv, 0);
printf("The program ran to completion without error. \n");

}// End of main

//--------------------------------------------------------------------
// This example uses the function MyHandleError, a simple error
// handling function, to print an error message and exit
// the program.
// For most applications, replace this function with one
// that does more extensive error reporting.

void MyHandleError(char *s)
{
printf("An error occurred in running the program.\n");
printf("%s\n",s);
printf("Error number %x\n.",GetLastError());
printf("Program terminating.\n");
exit(1);
}

=== code snippet end ===

Контейнер "qqqq" существует, ключ обмена в нем имеется. Первый же вызов CryptExportKey (для определения длины BLOB’а) возвращает NTE_BAD_KEY_STATE. Про какой из ключей это сообщается и что это значит?

ОС: Windows 2000 SP4
КП CSP: 2.0.2049

Ответы:

24.08.2004 17:13:01

Василий

Дело в том, что сессионный ключ экспортируется на ключе парной связи, полученном по алгоритму Диффи-Хеллмана из собственного закрытого ключа и открытого ключа получателя.
Пример см. http://www.cryptopro.ru/CryptoPro/forum/myforum.asp?q=4