SecPkgContext_Sizes structure (sspi.h)

The SecPkgContext_Sizes structure indicates the sizes of important structures used in the message support functions. The QueryContextAttributes (General) function uses this structure.


typedef struct _SecPkgContext_Sizes {
  unsigned long cbMaxToken;
  unsigned long cbMaxSignature;
  unsigned long cbBlockSize;
  unsigned long cbSecurityTrailer;
} SecPkgContext_Sizes, *PSecPkgContext_Sizes;



Specifies the maximum size of the security token used in the authentication exchanges.


Specifies the maximum size of the signature created by the MakeSignature function. This member must be zero if integrity services are not requested or available.


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.


Size of the security trailer to be appended to messages. This member should be zero if the relevant services are not requested or available.


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)