The MQFreeSecurityContext function frees the memory allocated by MQGetSecurityContext.
VOID APIENTRY MQFreeSecurityContext(
  HANDLE hSecurityContext  
);
 None
The security context buffer is created by MQGetSecurityContext. It contains information MSMQ needs to authenticate messages.
  Windows NT: Requires version 4.0 SP3 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in mq.h.
  Import Library: Use mqrt.lib.
  Unicode: Defined only as Unicode.