The CryptSetProvider function is used to specify the current user default CSP.
After this function has been called, any calls this user subsequently makes to CryptAcquireContext specifying the dwProvType provider type but not a provider name, will result in the pszProvName provider being used.
Note Typical applications will not use this function. It is intended for sole use by administrative applications.
BOOL CRYPTFUNC CryptSetProvider(
|
LPCTSTR pszProvName, | |
|
DWORD dwProvType | |
|
); |
Well-behaved applications do not usually specify a CSP name when calling the CryptAcquireContext function. This gives the users a certain amount of freedom in that they can select a CSP that has an appropriate level of security.
This means that a call to CryptSetProvider will often determine the CSP of a given type used by all applications that run from that point on. With this being the case, the CryptSetProvider function should never be called without the user’s consent.
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero. To retrieve extended error information, use the GetLastError function.
The following table lists the error codes most commonly returned by the GetLastError function.
|
Error |
Description |
|
ERROR_INVALID_HANDLE |
One of the parameters specifies an invalid handle. |
|
ERROR_INVALID_PARAMETER |
One of the parameters contains an invalid value. This is most often an illegal pointer. |
|
ERROR_NOT_ENOUGH_MEMORY |
The operating system ran out of memory during the operation. |
|
Error codes returned from the RegCreateKeyEx function. |
See RegCreateKeyEx. |
|
Error codes returned from the RegSetValueEx function. |
See RegSetValueEx. |
HCRYPTPROV hProv = 0;
// Specify the default PROV_RSA_SIG provider. Note that this assumes
// that a CSP with a type of PROV_RSA_SIG and named "Joe's Provider"
// has already been installed.
if(!CryptSetProvider(TEXT("Joe's Provider"), PROV_RSA_SIG)) {
printf("Error %x during CryptSetProvider!\n", GetLastError());
return;
}
// Get handle to the provider that we just made default.
if(!CryptAcquireContext(&hProv, NULL, NULL, PROV_RSA_SIG, 0)) {
printf("Error %x during CryptAcquireContext!\n", GetLastError());
return;
}
...
// Release provider handle.
if(!CryptReleaseContext(hProv, 0)) {
printf("Error %x during CryptReleaseContext!\n", GetLastError());
return;
}