SecPkgContext_StreamSizes structure (sspi.h)

The SecPkgContext_StreamSizes structure indicates the sizes of the various parts of a stream for use with the message support functions. The QueryContextAttributes (General) function uses this structure.

Syntax

typedef struct _SecPkgContext_StreamSizes {
  unsigned long cbHeader;
  unsigned long cbTrailer;
  unsigned long cbMaximumMessage;
  unsigned long cBuffers;
  unsigned long cbBlockSize;
} SecPkgContext_StreamSizes, *PSecPkgContext_StreamSizes;

Members

cbHeader

Specifies the size, in bytes, of the header portion. If zero, no header is used.

cbTrailer

Specifies the maximum size, in bytes, of the trailer portion. If zero, no trailer is used.

cbMaximumMessage

Specifies the size, in bytes, of the largest message that can be encapsulated.

cBuffers

Specifies the number of buffers to pass.

cbBlockSize

Specifies the preferred integral size of the messages. For example, eight indicates that messages should be of size zero mod eight for optimal performance. Messages other than this block size can be padded.

Remarks

Applications calling EncryptMessage (General) should check the values of the cbHeader, cbTrailer, and cbMaximumMessage members to determine the size of the encrypted packet.

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Header	sspi.h (include Security.h)

See also

QueryContextAttributes (General)