GetCryptProvFromCert function

Article
01/07/2021

Important

This API is deprecated. Microsoft may remove this API in future releases.

The GetCryptProvFromCert function gets a handle to a cryptographic service provider (CSP) and a key specification for a certificate context. Use this function to get access to the private key of the certificate issuer.

Note

This function has no associated header file or import library. To call this function, you must create a user-defined header file and use the LoadLibrary and GetProcAddress functions to dynamically link to Mssign32.dll.

Syntax

BOOL WINAPI GetCryptProvFromCert(
  _In_      HWND           hwnd,
  _In_      PCCERT_CONTEXT pCert,
  _Out_     HCRYPTPROV     *phCryptProv,
  _Out_     DWORD          *pdwKeySpec,
  _In_      BOOL           *pfDidCryptAcquire,
  _Out_opt_ LPWSTR         *ppwszTmpContainer,
  _Out_opt_ LPWSTR         *ppwszProviderName,
  _Out_     DWORD          *pdwProviderType
);

Parameters

hwnd [in]: The handle of the window to use as the owner of any dialog boxes that are displayed. This member is not currently used and is ignored. It is safe to pass NULL for this parameter.
pCert [in]: A pointer to a CERT_CONTEXT structure for the certificate.
phCryptProv [out]: A pointer to an HCRYPTPROV structure that is a handle to the CSP.
pdwKeySpec [out]: The specification of the private key to retrieve. Possible values include AT_KEYEXCHANGE or AT_SIGNATURE.
pfDidCryptAcquire [in]: A value that specifies whether the function acquired the provider handle based on the certificate.
ppwszTmpContainer [out, optional]: The address of a pointer to a null-terminated string for the temporary key container name. The GetCryptProvFromCert function provides and initializes the temporary container. When calling GetCryptProvFromCert, the address should point to a NULL value.
ppwszProviderName [out, optional]: The address of a pointer to a null-terminated string for the provider name. The GetCryptProvFromCert function returns the provider name. When calling GetCryptProvFromCert, the address should point to a NULL value.
pdwProviderType [out]: Specifies the CSP type. This can be zero or one of the Cryptographic Provider Types. If this member is zero, the key container is one of the CNG key storage providers.

Return value

Upon success, this function returns TRUE. The GetCryptProvFromCert function returns FALSE if it fails.

Remarks

The MakeCert tool calls GetCryptProvFromCert when you invoke it by using the -is command line option.

If the pfDidCryptAcquire parameter is set to TRUE, the function sets phCryptProv, pdwKeySpec, and pdwProviderType parameters to the provider values.

When you have finished using the CSP, free it by calling the FreeCryptProvFromCert function.

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
DLL	Mssign32.dll

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