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PROVIDER-MAC(7ossl)                  OpenSSL                 PROVIDER-MAC(7ossl)


       provider-mac - The mac library <-> provider functions


        #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_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[]);


       This documentation is primarily aimed at provider authors. See
       provider(7) for further information.

       The MAC operation enables providers to implement mac algorithms and make
       them available to applications via the API functions EVP_MAC_init(3),
       EVP_MAC_update(3) and EVP_MAC_final(3).

       All "functions" mentioned here are passed as function pointers between
       libcrypto and the provider in OSSL_DISPATCH(3) arrays via
       OSSL_ALGORITHM(3) arrays that are returned by the provider's
       provider_query_operation() function (see "Provider Functions" in

       All these "functions" have a corresponding function type definition named
       OSSL_FUNC_{name}_fn, and a helper function to retrieve the function
       pointer from an OSSL_DISPATCH(3) element named OSSL_FUNC_{name}.  For
       example, the "function" OSSL_FUNC_mac_newctx() has these:

        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);

       OSSL_DISPATCH(3) arrays are indexed by numbers that are provided as
       macros in openssl-core_dispatch.h(7), as follows:

        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_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

       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: OSSL_FUNC_mac_newctx(),
       OSSL_FUNC_mac_freectx(), OSSL_FUNC_mac_init(), OSSL_FUNC_mac_update(),
       OSSL_FUNC_mac_final().  All other functions are optional.

   Context Management Functions
       OSSL_FUNC_mac_newctx() 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 provctx is the provider context
       generated during provider initialisation (see provider(7)).

       OSSL_FUNC_mac_freectx() is passed a pointer to the provider side mac
       context in the mctx parameter.  If it receives NULL as mctx value, it
       should not do anything other than return.  This function should free any
       resources associated with that context.

       OSSL_FUNC_mac_dupctx() should duplicate the provider side mac context in
       the mctx parameter and return the duplicate copy.

   Encryption/Decryption Functions
       OSSL_FUNC_mac_init() initialises a mac operation given a newly created
       provider side mac context in the mctx parameter.  The params are set
       before setting the MAC key of keylen bytes.

       OSSL_FUNC_mac_update() is called to supply data for MAC computation of a
       previously initialised mac operation.  The mctx parameter contains a
       pointer to a previously initialised provider side context.
       OSSL_FUNC_mac_update() may be called multiple times for a single mac

       OSSL_FUNC_mac_final() completes the MAC computation started through
       previous OSSL_FUNC_mac_init() and OSSL_FUNC_mac_update() calls.  The mctx
       parameter contains a pointer to the provider side context.  The resulting
       MAC should be written to out and the amount of data written to *outl,
       which should not exceed outsize bytes.  The same expectations apply to
       outsize as documented for EVP_MAC_final(3).

   Mac Parameters
       See OSSL_PARAM(3) for further details on the parameters structure used by
       these functions.

       OSSL_FUNC_mac_get_params() gets details of parameter values associated
       with the provider algorithm and stores them in params.

       OSSL_FUNC_mac_set_ctx_params() sets mac parameters associated with the
       given provider side mac context mctx to params.  Any parameter settings
       are additional to any that were previously set.  Passing NULL for params
       should return true.

       OSSL_FUNC_mac_get_ctx_params() gets details of currently set parameter
       values associated with the given provider side mac context mctx and
       stores them in params.  Passing NULL for params should return true.

       OSSL_FUNC_mac_gettable_params(), OSSL_FUNC_mac_gettable_ctx_params(), and
       OSSL_FUNC_mac_settable_ctx_params() all return constant OSSL_PARAM(3)
       arrays as descriptors of the parameters that OSSL_FUNC_mac_get_params(),
       OSSL_FUNC_mac_get_ctx_params(), and OSSL_FUNC_mac_set_ctx_params() can
       handle, respectively.  OSSL_FUNC_mac_gettable_ctx_params() and
       OSSL_FUNC_mac_settable_ctx_params() will return the parameters associated
       with the provider side context mctx in its current state if it is not
       NULL.  Otherwise, they return the parameters associated with the provider
       side algorithm provctx.

       All MAC implementations are expected to handle the following parameters:

       with OSSL_FUNC_set_ctx_params():
           "key" (OSSL_MAC_PARAM_KEY) <octet string>
               Sets the key in the associated MAC ctx.  This is identical to
               passing a key argument to the OSSL_FUNC_mac_init() function.

       with OSSL_FUNC_get_params():
           "size" (OSSL_MAC_PARAM_SIZE) <integer>
               Can be used to get the default MAC size (which might be the only
               allowable MAC size for the implementation).

               Note that some implementations allow setting the size that the
               resulting MAC should have as well, see the documentation of the

           "size" (OSSL_MAC_PARAM_BLOCK_SIZE) <integer>
               Can be used to get the MAC block size (if supported by the


       The MAC life-cycle is described in life_cycle-rand(7).  Providers should
       ensure that the various transitions listed there are supported.  At some
       point the EVP layer will begin enforcing the listed transitions.


       OSSL_FUNC_mac_newctx() and OSSL_FUNC_mac_dupctx() should return the newly
       created provider side mac context, or NULL on failure.

       OSSL_FUNC_mac_init(), OSSL_FUNC_mac_update(), OSSL_FUNC_mac_final(),
       OSSL_FUNC_mac_get_params(), OSSL_FUNC_mac_get_ctx_params() and
       OSSL_FUNC_mac_set_ctx_params() should return 1 for success or 0 on error.

       OSSL_FUNC_mac_gettable_params(), OSSL_FUNC_mac_gettable_ctx_params() and
       OSSL_FUNC_mac_settable_ctx_params() should return a constant
       OSSL_PARAM(3) array, or NULL if none is offered.


       provider(7), EVP_MAC-BLAKE2(7), EVP_MAC-CMAC(7), EVP_MAC-GMAC(7),
       EVP_MAC-HMAC(7), EVP_MAC-KMAC(7), EVP_MAC-Poly1305(7),
       EVP_MAC-Siphash(7), life_cycle-mac(7), EVP_MAC(3)


       The provider MAC interface was introduced in OpenSSL 3.0.


       Copyright 2019-2022 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at

3.0.8                              2023-02-07                PROVIDER-MAC(7ossl)

openssl 3.0.8 - Generated Wed Feb 8 15:36:29 CST 2023
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