示例 C 程序：创建密钥容器和生成密钥
以下示例创建一个命名 密钥容器 ，并将 签名密钥对 和 交换密钥对 添加到该容器。 即使命名密钥容器和加密密钥已存在，也可以毫无问题地运行此示例。
注意
应用程序不应使用默认密钥容器来存储私钥。 当多个应用程序使用同一容器时，一个应用程序可能会更改或销毁另一个应用程序需要提供的密钥。 建议应用程序使用链接到应用程序的关键容器。 这样做可降低其他应用程序篡改应用程序正常运行所需的密钥的风险。
此示例演示以下任务和 CryptoAPI 函数：
- 它尝试获取命名密钥容器。 如果命名的密钥容器尚不存在，则会创建它。
- 如果密钥容器中不存在签名密钥对，则会在密钥容器中创建签名密钥对。
- 如果密钥容器中不存在交换密钥对，则会在密钥容器中创建交换密钥对。
这些操作只需为每台计算机上的每个用户执行一次。 如果已创建命名密钥容器和密钥对，则此示例不执行任何操作。
此示例使用以下 CryptoAPI 函数：
此示例使用函数 MyHandleError。 此示例中包含此函数的代码。 此函数和其他辅助函数的代码也列在常规用途函数下。
//-------------------------------------------------------------------
// Copyright (C) Microsoft. All rights reserved.
#pragma comment(lib, "crypt32.lib")
#include <stdio.h>
#include <tchar.h>
#include <windows.h>
#include <Wincrypt.h>
//-------------------------------------------------------------------
// 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(LPTSTR psz)
{
_ftprintf(stderr, TEXT("An error occurred in the program. \n"));
_ftprintf(stderr, TEXT("%s\n"), psz);
_ftprintf(stderr, TEXT("Error number %x.\n"), GetLastError());
_ftprintf(stderr, TEXT("Program terminating. \n"));
exit(1);
} // End of MyHandleError.
void main(void)
{
// Handle for the cryptographic provider context.
HCRYPTPROV hCryptProv;
// The name of the container.
LPCTSTR pszContainerName = TEXT("My Sample Key Container");
//---------------------------------------------------------------
// Begin processing. Attempt to acquire a context by using the
// specified key container.
if(CryptAcquireContext(
&hCryptProv,
pszContainerName,
NULL,
PROV_RSA_FULL,
0))
{
_tprintf(
TEXT("A crypto context with the %s key container ")
TEXT("has been acquired.\n"),
pszContainerName);
}
else
{
//-----------------------------------------------------------
// Some sort of error occurred in acquiring the context.
// This is most likely due to the specified container
// not existing. Create a new key container.
if(GetLastError() == NTE_BAD_KEYSET)
{
if(CryptAcquireContext(
&hCryptProv,
pszContainerName,
NULL,
PROV_RSA_FULL,
CRYPT_NEWKEYSET))
{
_tprintf(TEXT("A new key container has been ")
TEXT("created.\n"));
}
else
{
MyHandleError(TEXT("Could not create a new key ")
TEXT("container.\n"));
}
}
else
{
MyHandleError(TEXT("CryptAcquireContext failed.\n"));
}
}
//---------------------------------------------------------------
// A context with a key container is available.
// Attempt to get the handle to the signature key.
// Public/private key handle.
HCRYPTKEY hKey;
if(CryptGetUserKey(
hCryptProv,
AT_SIGNATURE,
&hKey))
{
_tprintf(TEXT("A signature key is available.\n"));
}
else
{
_tprintf(TEXT("No signature key is available.\n"));
if(GetLastError() == NTE_NO_KEY)
{
//-------------------------------------------------------
// The error was that there is a container but no key.
// Create a signature key pair.
_tprintf(TEXT("The signature key does not exist.\n"));
_tprintf(TEXT("Create a signature key pair.\n"));
if(CryptGenKey(
hCryptProv,
AT_SIGNATURE,
0,
&hKey))
{
_tprintf(TEXT("Created a signature key pair.\n"));
}
else
{
MyHandleError(TEXT("Error occurred creating a ")
TEXT("signature key.\n"));
}
}
else
{
MyHandleError(TEXT("An error other than NTE_NO_KEY ")
TEXT("getting a signature key.\n"));
}
} // End if.
_tprintf(TEXT("A signature key pair existed, or one was ")
TEXT("created.\n\n"));
// Destroy the signature key.
if(hKey)
{
if(!(CryptDestroyKey(hKey)))
{
MyHandleError(TEXT("Error during CryptDestroyKey."));
}
hKey = NULL;
}
// Next, check the exchange key.
if(CryptGetUserKey(
hCryptProv,
AT_KEYEXCHANGE,
&hKey))
{
_tprintf(TEXT("An exchange key exists.\n"));
}
else
{
_tprintf(TEXT("No exchange key is available.\n"));
// Check to determine whether an exchange key
// needs to be created.
if(GetLastError() == NTE_NO_KEY)
{
// Create a key exchange key pair.
_tprintf(TEXT("The exchange key does not exist.\n"));
_tprintf(TEXT("Attempting to create an exchange key ")
TEXT("pair.\n"));
if(CryptGenKey(
hCryptProv,
AT_KEYEXCHANGE,
0,
&hKey))
{
_tprintf(TEXT("Exchange key pair created.\n"));
}
else
{
MyHandleError(TEXT("Error occurred attempting to ")
TEXT("create an exchange key.\n"));
}
}
else
{
MyHandleError(TEXT("An error other than NTE_NO_KEY ")
TEXT("occurred.\n"));
}
}
// Destroy the exchange key.
if(hKey)
{
if(!(CryptDestroyKey(hKey)))
{
MyHandleError(TEXT("Error during CryptDestroyKey."));
}
hKey = NULL;
}
// Release the CSP.
if(hCryptProv)
{
if(!(CryptReleaseContext(hCryptProv, 0)))
{
MyHandleError(TEXT("Error during CryptReleaseContext."));
}
}
_tprintf(TEXT("Everything is okay. A signature key "));
_tprintf(TEXT("pair and an exchange key exist in "));
_tprintf(TEXT("the %s key container.\n"), pszContainerName);
} // End main.