PFNCryptStreamOutputCallback callback function (ncryptprotect.h)

The PFNCryptStreamOutputCallback function receives encrypted or decrypted data from tasks started by using the NCryptStreamOpenToProtect or NCryptStreamOpenToUnprotect functions. This callback must be defined by your application using the following syntax.

Syntax

PFNCryptStreamOutputCallback Pfncryptstreamoutputcallback;

SECURITY_STATUS Pfncryptstreamoutputcallback(
  [in] void *pvCallbackCtxt,
  [in] const BYTE *pbData,
       SIZE_T cbData,
       BOOL fFinal
)
{...}

Parameters

[in] pvCallbackCtxt

Pointer to data that you can use to keep track of your application. The data is not modified by the data protection API.

[in] pbData

Pointer to a block of processed data that can be used by the application.

cbData

The size, in bytes, of the processed data pointed to by the pbData parameter.

fFinal

If this value is TRUE, the current data block is the last to be processed and this is the last time the callback will be called.

Return value

If you return any status code other than ERROR_SUCCESS from your implementation of this callback function, the stream encryption or decryption process will fail.

Remarks

Set a pointer to this callback function in the pfnStreamOutput member of the NCRYPT_PROTECT_STREAM_INFO structure. Set a pointer to the structure in the pStreamInfo parameter of the NCryptStreamOpenToProtect or NCryptStreamOpenToUnprotect functions.

You can use this callback to further process the encrypted or decrypted data. A common use of the function is to write the data to disk as it is received from the data protection API. The blocks of encrypted or unencrypted data are created by the NCryptStreamUpdate function.

Requirements

See also

CNG DPAPI Functions

NCRYPT_PROTECT_STREAM_INFO

NCryptStreamOpenToProtect

NCryptStreamOpenToUnprotect

NCryptStreamUpdate