CryptEncodeObject

The CryptEncodeObject function encodes a structure of type lpszStructType.

#include <wincrypt.h>
BOOL WINAPI CryptEncodeObject(
  DWORD dwEncodingType,      // in
  LPCSTR lpszStructType,     // in
  const void *pvStructInfo,  // in
  BYTE *pbEncoded,           // out
  DWORD *pcbEncoded          // in/out
);

Parameters

dwEncodingType
The type of encoding used. Note that either a certificate or message encoding type is required. If the low-order word containing the certificate encoding type is nonzero, then it is used. Otherwise, the high-order word containing the message encoding type is used. If both are specified, the certificate encoding type in the low-order word is used.

Currently defined encoding types are shown in the following table.
Encoding type Value
CRYPT_ASN_ENCODING 0x00000001
X509_ASN_ENCODING 0x00000001
PKCS_7_ASN_ENCODING 0x00010000

lpszStructType
A pointer to an OID defining the structure type. If the high-order word of the lpszStructType parameter is zero, the low-order word specifies the integer identifier for the type of the given structure. Otherwise, this parameter is a long pointer to a null-terminated string.

For more details, see the table in CryptEncodeObject/CryptDecodeObject Functions that relates object identifier strings and predefined constants to their corresponding data structures.

pvStructInfo
A pointer to the structure to be encoded. The structure must be of a type specified by lpszStructType.
pbEncoded
Pointer to a buffer that receives the encoded structure. When the buffer that is specified is not large enough to receive the decoded structure, the function sets ERROR_MORE_DATA and stores the required buffer size, in bytes, into the variable pointed to by pcbEncoded.

This parameter can be NULL to set the size of this information for memory allocation purposes. For more information, see Common In/Out Parameter Conventions.

pcbEncoded
Pointer to a variable that specifies the size, in bytes, of the buffer pointed to by the pbEncoded parameter. When the function returns, this variable contains the size of the encoded data copied to *pbEncoded. This parameter can be NULL, only if pbEncoded is NULL.

Note  When processing the data returned in the buffer, applications need to use the actual size of the data returned. The actual size may be slightly smaller than the size of the buffer specified on input. (On input, buffer sizes are usually specified large enough to insure that the largest possible output data will fit in the buffer.) On output, the variable pointed to by this parameter is updated to reflect the actual size of the data copied to the buffer.

Return Values

TRUE if this function succeeded. FALSE if this function failed.

Call GetLastError to see the reason for any failures. This function has the following error codes.

Error code Description
CRYPT_E_BAD_ENCODE An error was encountered while encoding.
CRYPT_E_OSS_ERROR ASN.1 encoding error. Note, to get the OSS error subtract CRYPT_E_OSS_ERROR from the returned error and see asn1code.h for details on the error.
ERROR_FILE_NOT_FOUND An encoding function could not be found for the specified dwEncodingType and lpszStructType.
ERROR_MORE_DATA If the buffer specified by the pbEncoded 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, in the variable pointed to by pcbEncoded.

Example

See Certificate Request Example Code.

QuickInfo

  Windows NT: Requires version 4.0 SP3 or later. Available also in IE 3.02 and later.
  Windows: Requires Windows 98 (or Windows 95 with IE 3.02 or later).
  Windows CE: Unsupported.
  Header: Declared in wincrypt.h.
  Import Library: Use crypt32.lib.

See Also

CryptDecodeObject