CryptExportPublicKeyInfo function (wincrypt.h)
The CryptExportPublicKeyInfo function exports the public key information associated with the corresponding private key of the provider. For an updated version of this function, see CryptExportPublicKeyInfoEx.
Syntax
BOOL CryptExportPublicKeyInfo(
[in] HCRYPTPROV_OR_NCRYPT_KEY_HANDLE hCryptProvOrNCryptKey,
[in] DWORD dwKeySpec,
[in] DWORD dwCertEncodingType,
[out] PCERT_PUBLIC_KEY_INFO pInfo,
[in, out] DWORD *pcbInfo
);
Parameters
[in] hCryptProvOrNCryptKey
Handle of the cryptographic service provider (CSP) to use when exporting the public key information. This handle must be an HCRYPTPROV handle that has been created by using the CryptAcquireContext function or an NCRYPT_KEY_HANDLE handle that has been created by using the NCryptOpenKey function. New applications should always pass in the NCRYPT_KEY_HANDLE handle of a CNG CSP.
[in] dwKeySpec
Identifies the private key to use from the container of the provider. It can be AT_KEYEXCHANGE or AT_SIGNATURE. This parameter is ignored if an NCRYPT_KEY_HANDLE is used in the hCryptProvOrNCryptKey parameter.
[in] dwCertEncodingType
Specifies the encoding type used. It is always acceptable to specify both the certificate and message encoding types by combining them with a bitwise-OR operation as shown in the following example:
X509_ASN_ENCODING | PKCS_7_ASN_ENCODING
Currently defined encoding types are:
- X509_ASN_ENCODING
- PKCS_7_ASN_ENCODING
[out] pInfo
A pointer to a CERT_PUBLIC_KEY_INFO structure to receive the public key information to be exported.
To set the size of this information for memory allocation purposes, this parameter can be NULL. For more information, see Retrieving Data of Unknown Length.
[in, out] pcbInfo
A pointer to a DWORD that contains the size, in bytes, of the buffer pointed to by the pInfo parameter. When the function returns, the DWORD contains the number of bytes needed for the return buffer.
Return value
If the function succeeds, the function returns nonzero (TRUE).
If the function fails, it returns zero (FALSE). For extended error information, call GetLastError.
Return code | Description |
---|---|
|
If the buffer specified by the pInfo parameter is not large enough to hold the returned data, the function sets the ERROR_MORE_DATA code, and stores the required buffer size, in bytes, into the variable pointed to by pcbInfo. |
|
Invalid certificate encoding type. Currently only X509_ASN_ENCODING is supported. |
If the function fails, GetLastError may return an Abstract Syntax Notation One (ASN.1) encoding/decoding error. For information about these errors, see ASN.1 Encoding/Decoding Return Values.
Requirements
Requirement | Value |
---|---|
Minimum supported client | Windows XP [desktop apps only] |
Minimum supported server | Windows Server 2003 [desktop apps only] |
Target Platform | Windows |
Header | wincrypt.h |
Library | Crypt32.lib |
DLL | Crypt32.dll |