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.\"	$FreeBSD: head/lib/libgssapi/gss_get_mic.3 276381 2014-12-29 21:52:32Z joel $
.\"
.\" The following commands are required for all man pages.
.Dd January 26, 2010
.Dt GSS_GET_MIC 3 PRM
.Os
.Sh NAME
.Nm gss_get_mic ,
.Nm gss_sign
.Nd Calculate a cryptographic message integrity code (MIC) for a
message; integrity service
.\" This next command is for sections 2 and 3 only.
.\" .Sh LIBRARY
.Sh SYNOPSIS
.In "gssapi/gssapi.h"
.Ft OM_uint32
.Fo gss_get_mic
.Fa "OM_uint32 *minor_status"
.Fa "const gss_ctx_id_t context_handle"
.Fa "gss_qop_t qop_req"
.Fa "const gss_buffer_t message_buffer"
.Fa "gss_buffer_t msg_token"
.Fc
.Ft OM_uint32
.Fo gss_sign
.Fa "OM_uint32 *minor_status"
.Fa "const gss_ctx_id_t context_handle"
.Fa "gss_qop_t qop_req"
.Fa "gss_buffer_t message_buffer"
.Fa "gss_buffer_t msg_token"
.Fc
.Sh DESCRIPTION
Generates a cryptographic MIC for the supplied message,
and places the MIC in a token for transfer to the peer application.
The
.Fa qop_req
parameter allows a choice between several cryptographic algorithms,
if supported by the chosen mechanism.
.Pp
Since some application-level protocols may wish to use tokens emitted
by
.Fn gss_wrap
to provide "secure framing",
implementations must support derivation of MICs from zero-length messages.
.Pp
The
.Fn gss_sign
routine is an obsolete variant of
.Fn gss_get_mic .
It is
provided for backwards
compatibility with applications using the GSS-API V1 interface.
A distinct entrypoint (as opposed to #define) is provided,
both to allow GSS-API V1 applications to link
and to retain the slight parameter type differences between the
obsolete versions of this routine and its current form.
.Sh PARAMETERS
.Bl -tag -width ".It message_buffer"
.It minor_status
Mechanism specific status code.
.It context_handle
Identifies the context on which the message will be sent.
.It qop_req
Specifies requested quality of protection.
Callers are encouraged, on portability grounds,
to accept the default quality of protection offered by the chosen
mechanism,
which may be requested by specifying
.Dv GSS_C_QOP_DEFAULT
for this parameter.
If an unsupported protection strength is requested,
.Fn gss_get_mic
will return a
.Fa major_status
of
.Dv GSS_S_BAD_QOP .
.It message_buffer
Message to be protected.
.It msg_token
Buffer to receive token.
The application must free storage associated with this buffer after
use with a call to
.Fn gss_release_buffer .
.El
.Sh RETURN VALUES
.Bl -tag -width ".It GSS_S_CONTEXT_EXPIRED"
.It GSS_S_COMPLETE
Successful completion
.It GSS_S_CONTEXT_EXPIRED
The context has already expired
.It GSS_S_NO_CONTEXT
The context_handle parameter did not identify a valid context
.It GSS_S_BAD_QOP
The specified QOP is not supported by the mechanism
.El
.Sh SEE ALSO
.Xr gss_release_buffer 3 ,
.Xr gss_wrap 3
.Sh STANDARDS
.Bl -tag -width ".It RFC 2743"
.It RFC 2743
Generic Security Service Application Program Interface Version 2, Update 1
.It RFC 2744
Generic Security Service API Version 2 : C-bindings
.El
.Sh HISTORY
The
.Nm
function first appeared in
.Fx 7.0 .
.Sh AUTHORS
John Wray, Iris Associates
.Sh COPYRIGHT
Copyright (C) The Internet Society (2000).  All Rights Reserved.
.Pp
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works.  However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
.Pp
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
.Pp
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.