SpUnsealMessageFn callback function (ntsecpkg.h)

Decrypts a message that was previously encrypted with the SpSealMessage function.

The SpUnsealMessage function is the dispatch function for the DecryptMessage (General) function of the Security Support Provider Interface.


SpUnsealMessageFn Spunsealmessagefn;

NTSTATUS Spunsealmessagefn(
  [in]  LSA_SEC_HANDLE ContextHandle,
  [in]  PSecBufferDesc MessageBuffers,
  [in]  ULONG MessageSequenceNumber,
  [out] PULONG QualityOfProtection


[in] ContextHandle

Handle of the security context used to seal the message.

[in] MessageBuffers

Pointer to a SecBufferDesc structure that contains the message buffers and a signature buffer.

[in] MessageSequenceNumber

Sequence number to assign to the message. Sequence numbers are optional and are used as protection against loss and insertion of messages. A value of zero indicates that sequence numbers are not in use.

[out] QualityOfProtection

Not used.

Return value

If the function succeeds, return STATUS_SUCCESS.

If the function fails, return an NTSTATUS code that indicates the reason it failed.


SSP/APs must implement the SpUnsealMessage function; however, the actual name given to the implementation is up to the developer.

A pointer to the SpUnsealMessage function is available in the SECPKG_USER_FUNCTION_TABLE structure received from the SpUserModeInitialize function.


Requirement Value
Minimum supported client Windows XP [desktop apps only]
Minimum supported server Windows Server 2003 [desktop apps only]
Target Platform Windows
Header ntsecpkg.h

See also

DecryptMessage (General)