BCryptQueryContextFunctionConfiguration function

[BCryptQueryContextFunctionConfiguration is available for use in the operating systems specified in the Requirements section. It may be altered or unavailable in subsequent versions.]

The BCryptQueryContextFunctionConfiguration function obtains the cryptographic function configuration information for an existing CNG context.

Syntax


NTSTATUS WINAPI BCryptQueryContextFunctionConfiguration(
  _In_    ULONG                          dwTable,
  _In_    LPCWSTR                        pszContext,
  _In_    ULONG                          dwInterface,
  _In_    LPCWSTR                        pszFunction,
  _Inout_ ULONG                          *pcbBuffer,
  _Inout_ PCRYPT_CONTEXT_FUNCTION_CONFIG *ppBuffer
);

Parameters

dwTable [in]

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

ValueMeaning
CRYPT_LOCAL

The context exists in the local-machine configuration table.

CRYPT_DOMAIN

This value is not available for use.

 

pszContext [in]

A pointer to a null-terminated Unicode string that contains the identifier of the context to obtain the function configuration information for.

dwInterface [in]

Identifies the cryptographic interface to obtain the function configuration information for. This can be one of the following values.

ValueMeaning
BCRYPT_ASYMMETRIC_ENCRYPTION_INTERFACE

Obtain the function configuration information from the list of asymmetric encryption functions.

BCRYPT_CIPHER_INTERFACE

Obtain the function configuration information from the list of cipher functions.

BCRYPT_HASH_INTERFACE

Obtain the function configuration information from the list of hash functions.

BCRYPT_RNG_INTERFACE

Obtain the function configuration information from the list of random number generator functions.

BCRYPT_SECRET_AGREEMENT_INTERFACE

Obtain the function configuration information from the list of secret agreement functions.

BCRYPT_SIGNATURE_INTERFACE

Obtain the function configuration information from the list of signature functions.

NCRYPT_KEY_STORAGE_INTERFACE

Obtain the function configuration information from the list of key storage functions.

NCRYPT_SCHANNEL_INTERFACE

Obtain the function configuration information from the list of Schannel functions.

 

pszFunction [in]

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

pcbBuffer [in, out]

The address of a ULONG variable that, on entry, contains the size, in bytes, of the buffer pointed to by ppBuffer. If this size is not large enough to hold the context information, 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 ppBuffer buffer.

ppBuffer [in, out]

The address of a pointer to a CRYPT_CONTEXT_FUNCTION_CONFIG structure that receives the function configuration information retrieved by this function. The value pointed to by the pcbBuffer 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 pcbBuffer parameter and return STATUS_BUFFER_TOO_SMALL.

For more information about the usage of this parameter, see Remarks.

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 codeDescription
STATUS_SUCCESS

The function was successful.

STATUS_BUFFER_TOO_SMALL

The ppBuffer parameter is not NULL, and the value pointed to by the pcbBuffer 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 or function could not be found.

 

Remarks

Each cryptographic function has only one set of configuration information, so although the ppBuffer parameter appears to be a used as an array, this function treats this as an array with only one element. The following example helps clarify how this parameter is used.


// Get the function configuration information.
CRYPT_CONTEXT_FUNCTION_CONFIG FuncConfig;
ULONG uSize = sizeof(FuncConfig);
PCRYPT_CONTEXT_FUNCTION_CONFIG pFuncConfig = &FuncConfig;
status = BCryptQueryContextFunctionConfiguration(
    CRYPT_LOCAL, 
    pszContext, 
    NCRYPT_SCHANNEL_INTERFACE,
    pszFunction,
    &uSize, 
    &pFuncConfig);


BCryptQueryContextFunctionConfiguration can be called only in user mode.

Requirements

Minimum supported client

Windows Vista [desktop apps only]

Minimum supported server

Windows Server 2008 [desktop apps only]

Header

Bcrypt.h

Library

Bcrypt.lib

DLL

Bcrypt.dll

See also

CRYPT_CONTEXT_FUNCTION_CONFIG

 

 

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