BCryptQueryContextFunctionProperty function (bcrypt.h)

Article
10/13/2021

The BCryptQueryContextFunctionProperty function obtains the value of a named property for a cryptographic function in an existing CNG context.

Syntax

NTSTATUS BCryptQueryContextFunctionProperty(
  [in]      ULONG   dwTable,
  [in]      LPCWSTR pszContext,
  [in]      ULONG   dwInterface,
  [in]      LPCWSTR pszFunction,
  [in]      LPCWSTR pszProperty,
  [in, out] ULONG   *pcbValue,
  [in, out] PUCHAR  *ppbValue
);

Parameters

[in] dwTable

Identifies the configuration table that the context exists in. This can be one of the following values.

Value	Meaning
CRYPT_LOCAL	The context exists in the local-machine configuration table.
CRYPT_DOMAIN	This value is not available for use.

[in] pszContext

A pointer to a null-terminated Unicode string that contains the identifier of the context to obtain the function property from.

[in] dwInterface

Identifies the cryptographic interface that the function exists in. This can be one of the following values.

Value	Meaning
BCRYPT_ASYMMETRIC_ENCRYPTION_INTERFACE	The function exists in the list of asymmetric encryption functions.
BCRYPT_CIPHER_INTERFACE	The function exists in the list of cipher functions.
BCRYPT_HASH_INTERFACE	The function exists in the list of hash functions.
BCRYPT_RNG_INTERFACE	The function exists in the list of random number generator functions.
BCRYPT_SECRET_AGREEMENT_INTERFACE	The function exists in the list of secret agreement functions.
BCRYPT_SIGNATURE_INTERFACE	The function exists in the list of signature functions.
NCRYPT_KEY_STORAGE_INTERFACE	The function exists in the list of key storage functions.
NCRYPT_SCHANNEL_INTERFACE	The function exists in the list of Schannel functions.

[in] pszFunction

A pointer to a null-terminated Unicode string that contains the identifier of the cryptographic function to obtain the property for.

[in] pszProperty

A pointer to a null-terminated Unicode string that contains the identifier of the property to obtain.

[in, out] pcbValue

The address of a ULONG variable that, on entry, contains the size, in bytes, of the buffer pointed to by ppbValue. If this size is not large enough to hold the property value, this function will fail with STATUS_BUFFER_TOO_SMALL.

After this function returns, this variable contains the number of bytes that were copied to the ppbValue buffer.

[in, out] ppbValue

The address of a pointer to a buffer that receives the property data. The size and format of this buffer depends on the format of the property being retrieved. The value pointed to by the pcbValue parameter contains the size of this buffer.

If the value pointed to by this parameter is NULL, this function will allocate the required memory. This memory must be freed when it is no longer needed by passing this pointer to the BCryptFreeBuffer function.

If this parameter is NULL, this function will place the required size, in bytes, in the variable pointed to by the pcbValue parameter and return STATUS_BUFFER_TOO_SMALL.

Return value

Returns a status code that indicates the success or failure of the function.

Possible return codes include, but are not limited to, the following.

Return code	Description
STATUS_SUCCESS	The function was successful.
STATUS_BUFFER_TOO_SMALL	The ppbValue parameter is not NULL, and the value pointed to by the pcbValue parameter is not large enough to hold the set of contexts.
STATUS_INVALID_PARAMETER	One or more parameters are not valid.
STATUS_NO_MEMORY	A memory allocation failure occurred.
STATUS_NOT_FOUND	The specified context, function, or property could not be found.

Remarks

BCryptQueryContextFunctionProperty can be called only in user mode.

Requirements

Requirement	Value
Minimum supported client	Windows Vista [desktop apps only]
Minimum supported server	Windows Server 2008 [desktop apps only]
Target Platform	Windows
Header	bcrypt.h
Library	Bcrypt.lib
DLL	Bcrypt.dll

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