.\" Automatically generated by Pod::Man 4.14 (Pod::Simple 3.43)
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" Set up some character translations and predefined strings.  \*(-- will
.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
.\" double quote, and \*(R" will give a right double quote.  \*(C+ will
.\" give a nicer C++.  Capital omega is used to do unbreakable dashes and
.\" therefore won't be available.  \*(C` and \*(C' expand to `' in nroff,
.\" nothing in troff, for use with C<>.
.tr \(*W-
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.ie n \{\
.    ds -- \(*W-
.    ds PI pi
.    if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
.    if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\"  diablo 12 pitch
.    ds L" ""
.    ds R" ""
.    ds C` ""
.    ds C' ""
'br\}
.el\{\
.    ds -- \|\(em\|
.    ds PI \(*p
.    ds L" ``
.    ds R" ''
.    ds C`
.    ds C'
'br\}
.\"
.\" Escape single quotes in literal strings from groff's Unicode transform.
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\"
.\" If the F register is >0, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.\"
.\" Avoid warning from groff about undefined register 'F'.
.de IX
..
.nr rF 0
.if \n(.g .if rF .nr rF 1
.if (\n(rF:(\n(.g==0)) \{\
.    if \nF \{\
.        de IX
.        tm Index:\\$1\t\\n%\t"\\$2"
..
.        if !\nF==2 \{\
.            nr % 0
.            nr F 2
.        \}
.    \}
.\}
.rr rF
.\"
.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
.\" Fear.  Run.  Save yourself.  No user-serviceable parts.
.    \" fudge factors for nroff and troff
.if n \{\
.    ds #H 0
.    ds #V .8m
.    ds #F .3m
.    ds #[ \f1
.    ds #] \fP
.\}
.if t \{\
.    ds #H ((1u-(\\\\n(.fu%2u))*.13m)
.    ds #V .6m
.    ds #F 0
.    ds #[ \&
.    ds #] \&
.\}
.    \" simple accents for nroff and troff
.if n \{\
.    ds ' \&
.    ds ` \&
.    ds ^ \&
.    ds , \&
.    ds ~ ~
.    ds /
.\}
.if t \{\
.    ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
.    ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
.    ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
.    ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
.    ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
.    ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.\}
.    \" troff and (daisy-wheel) nroff accents
.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
.ds ae a\h'-(\w'a'u*4/10)'e
.ds Ae A\h'-(\w'A'u*4/10)'E
.    \" corrections for vroff
.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
.    \" for low resolution devices (crt and lpr)
.if \n(.H>23 .if \n(.V>19 \
\{\
.    ds : e
.    ds 8 ss
.    ds o a
.    ds d- d\h'-1'\(ga
.    ds D- D\h'-1'\(hy
.    ds th \o'bp'
.    ds Th \o'LP'
.    ds ae ae
.    ds Ae AE
.\}
.rm #[ #] #H #V #F C
.\" ========================================================================
.\"
.IX Title "PROVIDER-MAC 7ossl"
.TH PROVIDER-MAC 7ossl "2025-09-30" "3.5.4" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
provider\-mac \- The mac library <\-> provider functions
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 2
\& #include <openssl/core_dispatch.h>
\& #include <openssl/core_names.h>
\&
\& /*
\&  * None of these are actual functions, but are displayed like this for
\&  * the function signatures for functions that are offered as function
\&  * pointers in OSSL_DISPATCH arrays.
\&  */
\&
\& /* Context management */
\& void *OSSL_FUNC_mac_newctx(void *provctx);
\& void OSSL_FUNC_mac_freectx(void *mctx);
\& void *OSSL_FUNC_mac_dupctx(void *src);
\&
\& /* Encryption/decryption */
\& int OSSL_FUNC_mac_init(void *mctx, unsigned char *key, size_t keylen,
\&                        const OSSL_PARAM params[]);
\& int OSSL_FUNC_mac_init_skey(void *mctx, const void *key, const OSSL_PARAM params[]);
\& int OSSL_FUNC_mac_update(void *mctx, const unsigned char *in, size_t inl);
\& int OSSL_FUNC_mac_final(void *mctx, unsigned char *out, size_t *outl, size_t outsize);
\&
\& /* MAC parameter descriptors */
\& const OSSL_PARAM *OSSL_FUNC_mac_gettable_params(void *provctx);
\& const OSSL_PARAM *OSSL_FUNC_mac_gettable_ctx_params(void *mctx, void *provctx);
\& const OSSL_PARAM *OSSL_FUNC_mac_settable_ctx_params(void *mctx, void *provctx);
\&
\& /* MAC parameters */
\& int OSSL_FUNC_mac_get_params(OSSL_PARAM params[]);
\& int OSSL_FUNC_mac_get_ctx_params(void *mctx, OSSL_PARAM params[]);
\& int OSSL_FUNC_mac_set_ctx_params(void *mctx, const OSSL_PARAM params[]);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This documentation is primarily aimed at provider authors. See \fBprovider\fR\|(7)
for further information.
.PP
The \s-1MAC\s0 operation enables providers to implement mac algorithms and make
them available to applications via the \s-1API\s0 functions \fBEVP_MAC_init\fR\|(3),
\&\fBEVP_MAC_update\fR\|(3) and \fBEVP_MAC_final\fR\|(3).
.PP
All \*(L"functions\*(R" mentioned here are passed as function pointers between
\&\fIlibcrypto\fR and the provider in \s-1\fBOSSL_DISPATCH\s0\fR\|(3) arrays via
\&\s-1\fBOSSL_ALGORITHM\s0\fR\|(3) arrays that are returned by the provider's
\&\fBprovider_query_operation()\fR function
(see \*(L"Provider Functions\*(R" in \fBprovider\-base\fR\|(7)).
.PP
All these \*(L"functions\*(R" have a corresponding function type definition
named \fBOSSL_FUNC_{name}_fn\fR, and a helper function to retrieve the
function pointer from an \s-1\fBOSSL_DISPATCH\s0\fR\|(3) element named
\&\fBOSSL_FUNC_{name}\fR.
For example, the \*(L"function\*(R" \fBOSSL_FUNC_mac_newctx()\fR has these:
.PP
.Vb 3
\& typedef void *(OSSL_FUNC_mac_newctx_fn)(void *provctx);
\& static ossl_inline OSSL_FUNC_mac_newctx_fn
\&     OSSL_FUNC_mac_newctx(const OSSL_DISPATCH *opf);
.Ve
.PP
\&\s-1\fBOSSL_DISPATCH\s0\fR\|(3) arrays are indexed by numbers that are provided as
macros in \fBopenssl\-core_dispatch.h\fR\|(7), as follows:
.PP
.Vb 3
\& OSSL_FUNC_mac_newctx               OSSL_FUNC_MAC_NEWCTX
\& OSSL_FUNC_mac_freectx              OSSL_FUNC_MAC_FREECTX
\& OSSL_FUNC_mac_dupctx               OSSL_FUNC_MAC_DUPCTX
\&
\& OSSL_FUNC_mac_init                 OSSL_FUNC_MAC_INIT
\& OSSL_FUNC_mac_init_skey            OSSL_FUNC_MAC_INIT_SKEY
\& OSSL_FUNC_mac_update               OSSL_FUNC_MAC_UPDATE
\& OSSL_FUNC_mac_final                OSSL_FUNC_MAC_FINAL
\&
\& OSSL_FUNC_mac_get_params           OSSL_FUNC_MAC_GET_PARAMS
\& OSSL_FUNC_mac_get_ctx_params       OSSL_FUNC_MAC_GET_CTX_PARAMS
\& OSSL_FUNC_mac_set_ctx_params       OSSL_FUNC_MAC_SET_CTX_PARAMS
\&
\& OSSL_FUNC_mac_gettable_params      OSSL_FUNC_MAC_GETTABLE_PARAMS
\& OSSL_FUNC_mac_gettable_ctx_params  OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS
\& OSSL_FUNC_mac_settable_ctx_params  OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS
.Ve
.PP
A mac algorithm implementation may not implement all of these functions.
In order to be a consistent set of functions, at least the following functions
must be implemented: \fBOSSL_FUNC_mac_newctx()\fR, \fBOSSL_FUNC_mac_freectx()\fR,
at least one of \fBOSSL_FUNC_mac_init()\fR or \fBOSSL_FUNC_mac_init_skey()\fR,
\&\fBOSSL_FUNC_mac_update()\fR, \fBOSSL_FUNC_mac_final()\fR.
All other functions are optional.
.SS "Context Management Functions"
.IX Subsection "Context Management Functions"
\&\fBOSSL_FUNC_mac_newctx()\fR should create and return a pointer to a provider side
structure for holding context information during a mac operation.
A pointer to this context will be passed back in a number of the other mac
operation function calls.
The parameter \fIprovctx\fR is the provider context generated during provider
initialisation (see \fBprovider\fR\|(7)).
.PP
\&\fBOSSL_FUNC_mac_freectx()\fR is passed a pointer to the provider side mac context in
the \fImctx\fR parameter.
If it receives \s-1NULL\s0 as \fImctx\fR value, it should not do anything other than
return.
This function should free any resources associated with that context.
.PP
\&\fBOSSL_FUNC_mac_dupctx()\fR should duplicate the provider side mac context in the
\&\fImctx\fR parameter and return the duplicate copy.
.SS "Encryption/Decryption Functions"
.IX Subsection "Encryption/Decryption Functions"
\&\fBOSSL_FUNC_mac_init()\fR initialises a mac operation given a newly created provider
side mac context in the \fImctx\fR parameter.  The \fIparams\fR are set before setting
the \s-1MAC\s0 \fIkey\fR of \fIkeylen\fR bytes.
.PP
\&\fBOSSL_FUNC_mac_init_skey()\fR is similar but uses an opaque provider-specific object
to initialize the \s-1MAC\s0 context.
.PP
\&\fBOSSL_FUNC_mac_update()\fR is called to supply data for \s-1MAC\s0 computation of a previously
initialised mac operation.
The \fImctx\fR parameter contains a pointer to a previously initialised provider
side context.
\&\fBOSSL_FUNC_mac_update()\fR may be called multiple times for a single mac operation.
.PP
\&\fBOSSL_FUNC_mac_final()\fR completes the \s-1MAC\s0 computation started through previous
\&\fBOSSL_FUNC_mac_init()\fR and \fBOSSL_FUNC_mac_update()\fR calls.
The \fImctx\fR parameter contains a pointer to the provider side context.
The resulting \s-1MAC\s0 should be written to \fIout\fR and the amount of data written
to \fI*outl\fR, which should not exceed \fIoutsize\fR bytes.
The same expectations apply to \fIoutsize\fR as documented for
\&\fBEVP_MAC_final\fR\|(3).
.SS "Mac Parameters"
.IX Subsection "Mac Parameters"
See \s-1\fBOSSL_PARAM\s0\fR\|(3) for further details on the parameters structure used by
these functions.
.PP
\&\fBOSSL_FUNC_mac_get_params()\fR gets details of parameter values associated with the
provider algorithm and stores them in \fIparams\fR.
.PP
\&\fBOSSL_FUNC_mac_set_ctx_params()\fR sets mac parameters associated with the given
provider side mac context \fImctx\fR to \fIparams\fR.
Any parameter settings are additional to any that were previously set.
Passing \s-1NULL\s0 for \fIparams\fR should return true.
.PP
\&\fBOSSL_FUNC_mac_get_ctx_params()\fR gets details of currently set parameter values
associated with the given provider side mac context \fImctx\fR and stores them
in \fIparams\fR.
Passing \s-1NULL\s0 for \fIparams\fR should return true.
.PP
\&\fBOSSL_FUNC_mac_gettable_params()\fR, \fBOSSL_FUNC_mac_gettable_ctx_params()\fR,
and \fBOSSL_FUNC_mac_settable_ctx_params()\fR all return constant \s-1\fBOSSL_PARAM\s0\fR\|(3)
arrays as descriptors of the parameters that \fBOSSL_FUNC_mac_get_params()\fR,
\&\fBOSSL_FUNC_mac_get_ctx_params()\fR, and \fBOSSL_FUNC_mac_set_ctx_params()\fR
can handle, respectively.  \fBOSSL_FUNC_mac_gettable_ctx_params()\fR and
\&\fBOSSL_FUNC_mac_settable_ctx_params()\fR will return the parameters associated
with the provider side context \fImctx\fR in its current state if it is
not \s-1NULL.\s0  Otherwise, they return the parameters associated with the
provider side algorithm \fIprovctx\fR.
.PP
All \s-1MAC\s0 implementations are expected to handle the following parameters:
.IP "with \fBOSSL_FUNC_set_ctx_params()\fR:" 4
.IX Item "with OSSL_FUNC_set_ctx_params():"
.RS 4
.PD 0
.ie n .IP """key"" (\fB\s-1OSSL_MAC_PARAM_KEY\s0\fR) <octet string>" 4
.el .IP "``key'' (\fB\s-1OSSL_MAC_PARAM_KEY\s0\fR) <octet string>" 4
.IX Item "key (OSSL_MAC_PARAM_KEY) <octet string>"
.PD
Sets the key in the associated \s-1MAC\s0 ctx.  This is identical to passing a \fIkey\fR
argument to the \fBOSSL_FUNC_mac_init()\fR function.
.RE
.RS 4
.RE
.IP "with \fBOSSL_FUNC_get_params()\fR:" 4
.IX Item "with OSSL_FUNC_get_params():"
.RS 4
.PD 0
.ie n .IP """size"" (\fB\s-1OSSL_MAC_PARAM_SIZE\s0\fR) <integer>" 4
.el .IP "``size'' (\fB\s-1OSSL_MAC_PARAM_SIZE\s0\fR) <integer>" 4
.IX Item "size (OSSL_MAC_PARAM_SIZE) <integer>"
.PD
Can be used to get the default \s-1MAC\s0 size (which might be the only allowable
\&\s-1MAC\s0 size for the implementation).
.Sp
Note that some implementations allow setting the size that the resulting \s-1MAC\s0
should have as well, see the documentation of the implementation.
.RE
.RS 4
.ie n .IP """size"" (\fB\s-1OSSL_MAC_PARAM_BLOCK_SIZE\s0\fR) <integer>" 4
.el .IP "``size'' (\fB\s-1OSSL_MAC_PARAM_BLOCK_SIZE\s0\fR) <integer>" 4
.IX Item "size (OSSL_MAC_PARAM_BLOCK_SIZE) <integer>"
Can be used to get the \s-1MAC\s0 block size (if supported by the algorithm).
.RE
.RS 4
.RE
.PP
The OpenSSL \s-1FIPS\s0 provider may support the following parameters:
.ie n .IP """fips-indicator"" (\fB\s-1OSSL_MAC_PARAM_FIPS_APPROVED_INDICATOR\s0\fR) <int>" 4
.el .IP "``fips-indicator'' (\fB\s-1OSSL_MAC_PARAM_FIPS_APPROVED_INDICATOR\s0\fR) <int>" 4
.IX Item "fips-indicator (OSSL_MAC_PARAM_FIPS_APPROVED_INDICATOR) <int>"
A getter that returns 1 if the operation is \s-1FIPS\s0 approved, or 0 otherwise.
This may be used after calling the final function. It may return 0 if
either \*(L"no-short-mac\*(R" or \*(L"key-check\*(R" are set to 0.
.ie n .IP """no-short-mac"" (\fB\s-1OSSL_MAC_PARAM_FIPS_NO_SHORT_MAC\s0\fR) <integer>" 4
.el .IP "``no-short-mac'' (\fB\s-1OSSL_MAC_PARAM_FIPS_NO_SHORT_MAC\s0\fR) <integer>" 4
.IX Item "no-short-mac (OSSL_MAC_PARAM_FIPS_NO_SHORT_MAC) <integer>"
If required this parameter should be set early via an init function.
The default value of 1 causes an error when too short \s-1MAC\s0 output is
asked for.  Setting this to 0 will ignore the error and set the approved
\&\*(L"fips-indicator\*(R" to 0.
This option breaks \s-1FIPS\s0 compliance if it causes the approved \*(L"fips-indicator\*(R"
to return 0.
.ie n .IP """key-check"" (\fB\s-1OSSL_MAC_PARAM_FIPS_KEY_CHECK\s0\fR) <integer>" 4
.el .IP "``key-check'' (\fB\s-1OSSL_MAC_PARAM_FIPS_KEY_CHECK\s0\fR) <integer>" 4
.IX Item "key-check (OSSL_MAC_PARAM_FIPS_KEY_CHECK) <integer>"
If required this parameter should be set before OSSL_FUNC_mac_init.
The default value of 1 causes an error when small key sizes are
asked for.  Setting this to 0 will ignore the error and set the approved
\&\*(L"fips-indicator\*(R" to 0.
This option breaks \s-1FIPS\s0 compliance if it causes the approved \*(L"fips-indicator\*(R"
to return 0.
.SH "NOTES"
.IX Header "NOTES"
The \s-1MAC\s0 life-cycle is described in \fBlife_cycle\-rand\fR\|(7).  Providers should
ensure that the various transitions listed there are supported.  At some point
the \s-1EVP\s0 layer will begin enforcing the listed transitions.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fBOSSL_FUNC_mac_newctx()\fR and \fBOSSL_FUNC_mac_dupctx()\fR should return the newly created
provider side mac context, or \s-1NULL\s0 on failure.
.PP
\&\fBOSSL_FUNC_mac_init()\fR, \fBOSSL_FUNC_mac_init_skey()\fR,
\&\fBOSSL_FUNC_mac_update()\fR, \fBOSSL_FUNC_mac_final()\fR, \fBOSSL_FUNC_mac_get_params()\fR,
\&\fBOSSL_FUNC_mac_get_ctx_params()\fR and \fBOSSL_FUNC_mac_set_ctx_params()\fR should return 1 for
success or 0 on error.
.PP
\&\fBOSSL_FUNC_mac_gettable_params()\fR, \fBOSSL_FUNC_mac_gettable_ctx_params()\fR and
\&\fBOSSL_FUNC_mac_settable_ctx_params()\fR should return a constant \s-1\fBOSSL_PARAM\s0\fR\|(3)
array, or \s-1NULL\s0 if none is offered.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBprovider\fR\|(7),
\&\s-1\fBEVP_MAC\-BLAKE2\s0\fR\|(7), \s-1\fBEVP_MAC\-CMAC\s0\fR\|(7), \s-1\fBEVP_MAC\-GMAC\s0\fR\|(7),
\&\s-1\fBEVP_MAC\-HMAC\s0\fR\|(7), \s-1\fBEVP_MAC\-KMAC\s0\fR\|(7), \fBEVP_MAC\-Poly1305\fR\|(7),
\&\fBEVP_MAC\-Siphash\fR\|(7),
\&\fBlife_cycle\-mac\fR\|(7), \s-1\fBEVP_MAC\s0\fR\|(3)
.SH "HISTORY"
.IX Header "HISTORY"
The provider \s-1MAC\s0 interface was introduced in OpenSSL 3.0.
The parameters \*(L"no-short-mac\*(R" and \*(L"fips-indicator\*(R" were added in OpenSSL 3.4.
.PP
The function \fBOSSL_FUNC_mac_init_skey()\fR was introduced in OpenSSL 3.5.
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2019\-2025 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the Apache License 2.0 (the \*(L"License\*(R").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file \s-1LICENSE\s0 in the source distribution or at
<https://www.openssl.org/source/license.html>.
