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PROVIDER-KEYMGMT(7)                 OpenSSL                PROVIDER-KEYMGMT(7)



NAME
       provider-keymgmt - The KEYMGMT library <-> provider functions

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/core_dispatch.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.
         */

        /* Key object (keydata) creation and destruction */
        void *OSSL_FUNC_keymgmt_new(void *provctx);
        void OSSL_FUNC_keymgmt_free(void *keydata);

        /* Generation, a more complex constructor */
        void *OSSL_FUNC_keymgmt_gen_init(void *provctx, int selection,
                                         const OSSL_PARAM params[]);
        int OSSL_FUNC_keymgmt_gen_set_template(void *genctx, void *template);
        int OSSL_FUNC_keymgmt_gen_set_params(void *genctx, const OSSL_PARAM params[]);
        const OSSL_PARAM *OSSL_FUNC_keymgmt_gen_settable_params(void *genctx,
                                                                void *provctx);
        void *OSSL_FUNC_keymgmt_gen(void *genctx, OSSL_CALLBACK *cb, void *cbarg);
        void OSSL_FUNC_keymgmt_gen_cleanup(void *genctx);

        /* Key loading by object reference, also a constructor */
        void *OSSL_FUNC_keymgmt_load(const void *reference, size_t *reference_sz);

        /* Key object information */
        int OSSL_FUNC_keymgmt_get_params(void *keydata, OSSL_PARAM params[]);
        const OSSL_PARAM *OSSL_FUNC_keymgmt_gettable_params(void *provctx);
        int OSSL_FUNC_keymgmt_set_params(void *keydata, const OSSL_PARAM params[]);
        const OSSL_PARAM *OSSL_FUNC_keymgmt_settable_params(void *provctx);

        /* Key object content checks */
        int OSSL_FUNC_keymgmt_has(const void *keydata, int selection);
        int OSSL_FUNC_keymgmt_match(const void *keydata1, const void *keydata2,
                                    int selection);

        /* Discovery of supported operations */
        const char *OSSL_FUNC_keymgmt_query_operation_name(int operation_id);

        /* Key object import and export functions */
        int OSSL_FUNC_keymgmt_import(void *keydata, int selection, const OSSL_PARAM params[]);
        const OSSL_PARAM *OSSL_FUNC_keymgmt_import_types(int selection);
        int OSSL_FUNC_keymgmt_export(void *keydata, int selection,
                                     OSSL_CALLBACK *param_cb, void *cbarg);
        const OSSL_PARAM *OSSL_FUNC_keymgmt_export_types(int selection);

        /* Key object duplication, a constructor */
        void *OSSL_FUNC_keymgmt_dup(const void *keydata_from, int selection);

        /* Key object validation */
        int OSSL_FUNC_keymgmt_validate(const void *keydata, int selection, int checktype);

DESCRIPTION
       The KEYMGMT operation doesn't have much public visibility in OpenSSL
       libraries, it's rather an internal operation that's designed to work in
       tandem with operations that use private/public key pairs.

       Because the KEYMGMT operation shares knowledge with the operations it
       works with in tandem, they must belong to the same provider.  The
       OpenSSL libraries will ensure that they do.

       The primary responsibility of the KEYMGMT operation is to hold the
       provider side key data for the OpenSSL library EVP_PKEY structure.

       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
       provider-base(7)).

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

        typedef void *(OSSL_FUNC_keymgmt_new_fn)(void *provctx);
        static ossl_inline OSSL_FUNC_keymgmt_new_fn
            OSSL_FUNC_keymgmt_new(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_keymgmt_new                  OSSL_FUNC_KEYMGMT_NEW
        OSSL_FUNC_keymgmt_free                 OSSL_FUNC_KEYMGMT_FREE

        OSSL_FUNC_keymgmt_gen_init             OSSL_FUNC_KEYMGMT_GEN_INIT
        OSSL_FUNC_keymgmt_gen_set_template     OSSL_FUNC_KEYMGMT_GEN_SET_TEMPLATE
        OSSL_FUNC_keymgmt_gen_set_params       OSSL_FUNC_KEYMGMT_GEN_SET_PARAMS
        OSSL_FUNC_keymgmt_gen_settable_params  OSSL_FUNC_KEYMGMT_GEN_SETTABLE_PARAMS
        OSSL_FUNC_keymgmt_gen                  OSSL_FUNC_KEYMGMT_GEN
        OSSL_FUNC_keymgmt_gen_cleanup          OSSL_FUNC_KEYMGMT_GEN_CLEANUP

        OSSL_FUNC_keymgmt_load                 OSSL_FUNC_KEYMGMT_LOAD

        OSSL_FUNC_keymgmt_get_params           OSSL_FUNC_KEYMGMT_GET_PARAMS
        OSSL_FUNC_keymgmt_gettable_params      OSSL_FUNC_KEYMGMT_GETTABLE_PARAMS
        OSSL_FUNC_keymgmt_set_params           OSSL_FUNC_KEYMGMT_SET_PARAMS
        OSSL_FUNC_keymgmt_settable_params      OSSL_FUNC_KEYMGMT_SETTABLE_PARAMS

        OSSL_FUNC_keymgmt_query_operation_name OSSL_FUNC_KEYMGMT_QUERY_OPERATION_NAME

        OSSL_FUNC_keymgmt_has                  OSSL_FUNC_KEYMGMT_HAS
        OSSL_FUNC_keymgmt_validate             OSSL_FUNC_KEYMGMT_VALIDATE
        OSSL_FUNC_keymgmt_match                OSSL_FUNC_KEYMGMT_MATCH

        OSSL_FUNC_keymgmt_import               OSSL_FUNC_KEYMGMT_IMPORT
        OSSL_FUNC_keymgmt_import_types         OSSL_FUNC_KEYMGMT_IMPORT_TYPES
        OSSL_FUNC_keymgmt_export               OSSL_FUNC_KEYMGMT_EXPORT
        OSSL_FUNC_keymgmt_export_types         OSSL_FUNC_KEYMGMT_EXPORT_TYPES

        OSSL_FUNC_keymgmt_dup                  OSSL_FUNC_KEYMGMT_DUP

   Key Objects
       A key object is a collection of data for an asymmetric key, and is
       represented as keydata in this manual.

       The exact contents of a key object are defined by the provider, and it
       is assumed that different operations in one and the same provider use
       the exact same structure to represent this collection of data, so that
       for example, a key object that has been created using the KEYMGMT
       interface that we document here can be passed as is to other provider
       operations, such as OP_signature_sign_init() (see
       provider-signature(7)).

       With some of the KEYMGMT functions, it's possible to select a specific
       subset of data to handle, governed by the bits in a selection
       indicator.  The bits are:

       OSSL_KEYMGMT_SELECT_PRIVATE_KEY
           Indicating that the private key data in a key object should be
           considered.

       OSSL_KEYMGMT_SELECT_PUBLIC_KEY
           Indicating that the public key data in a key object should be
           considered.

       OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS
           Indicating that the domain parameters in a key object should be
           considered.

       OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS
           Indicating that other parameters in a key object should be
           considered.

           Other parameters are key parameters that don't fit any other
           classification.  In other words, this particular selector bit works
           as a last resort bit bucket selector.

       Some selector bits have also been combined for easier use:

       OSSL_KEYMGMT_SELECT_ALL_PARAMETERS
           Indicating that all key object parameters should be considered,
           regardless of their more granular classification.

           This is a combination of OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS and
           OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS.

       OSSL_KEYMGMT_SELECT_KEYPAIR
           Indicating that both the whole key pair in a key object should be
           considered, i.e. the combination of public and private key.

           This is a combination of OSSL_KEYMGMT_SELECT_PRIVATE_KEY and
           OSSL_KEYMGMT_SELECT_PUBLIC_KEY.

       OSSL_KEYMGMT_SELECT_ALL
           Indicating that everything in a key object should be considered.

       The exact interpretation of those bits or how they combine is left to
       each function where you can specify a selector.

       It's left to the provider implementation to decide what is reasonable
       to do with regards to received selector bits and how to do it.  Among
       others, an implementation of OSSL_FUNC_keymgmt_match() might opt to not
       compare the private half if it has compared the public half, since a
       match of one half implies a match of the other half.

   Constructing and Destructing Functions
       OSSL_FUNC_keymgmt_new() should create a provider side key object.  The
       provider context provctx is passed and may be incorporated in the key
       object, but that is not mandatory.

       OSSL_FUNC_keymgmt_free() should free the passed keydata.

       OSSL_FUNC_keymgmt_gen_init(), OSSL_FUNC_keymgmt_gen_set_template(),
       OSSL_FUNC_keymgmt_gen_set_params(),
       OSSL_FUNC_keymgmt_gen_settable_params(), OSSL_FUNC_keymgmt_gen() and
       OSSL_FUNC_keymgmt_gen_cleanup() work together as a more elaborate
       context based key object constructor.

       OSSL_FUNC_keymgmt_gen_init() should create the key object generation
       context and initialize it with selections, which will determine what
       kind of contents the key object to be generated should get.  The
       params, if not NULL, should be set on the context in a manner similar
       to using OSSL_FUNC_keymgmt_set_params().

       OSSL_FUNC_keymgmt_gen_set_template() should add template to the context
       genctx.  The template is assumed to be a key object constructed with
       the same KEYMGMT, and from which content that the implementation
       chooses can be used as a template for the key object to be generated.
       Typically, the generation of a DSA or DH key would get the domain
       parameters from this template.

       OSSL_FUNC_keymgmt_gen_set_params() should set additional parameters
       from params in the key object generation context genctx.

       OSSL_FUNC_keymgmt_gen_settable_params() should return a constant array
       of descriptor OSSL_PARAM(3), for parameters that
       OSSL_FUNC_keymgmt_gen_set_params() can handle.

       OSSL_FUNC_keymgmt_gen() should perform the key object generation
       itself, and return the result.  The callback cb should be called at
       regular intervals with indications on how the key object generation
       progresses.

       OSSL_FUNC_keymgmt_gen_cleanup() should clean up and free the key object
       generation context genctx

       OSSL_FUNC_keymgmt_load() creates a provider side key object based on a
       reference object with a size of reference_sz bytes, that only the
       provider knows how to interpret, but that may come from other
       operations.  Outside the provider, this reference is simply an array of
       bytes.

       At least one of OSSL_FUNC_keymgmt_new(), OSSL_FUNC_keymgmt_gen() and
       OSSL_FUNC_keymgmt_load() are mandatory, as well as
       OSSL_FUNC_keymgmt_free() and OSSL_FUNC_keymgmt_has(). Additionally, if
       OSSL_FUNC_keymgmt_gen() is present, OSSL_FUNC_keymgmt_gen_init() and
       OSSL_FUNC_keymgmt_gen_cleanup() must be present as well.

   Key Object Information Functions
       OSSL_FUNC_keymgmt_get_params() should extract information data
       associated with the given keydata, see "Common Information Parameters".

       OSSL_FUNC_keymgmt_gettable_params() should return a constant array of
       descriptor OSSL_PARAM(3), for parameters that
       OSSL_FUNC_keymgmt_get_params() can handle.

       If OSSL_FUNC_keymgmt_gettable_params() is present,
       OSSL_FUNC_keymgmt_get_params() must also be present, and vice versa.

       OSSL_FUNC_keymgmt_set_params() should update information data
       associated with the given keydata, see "Common Information Parameters".

       OSSL_FUNC_keymgmt_settable_params() should return a constant array of
       descriptor OSSL_PARAM(3), for parameters that
       OSSL_FUNC_keymgmt_set_params() can handle.

       If OSSL_FUNC_keymgmt_settable_params() is present,
       OSSL_FUNC_keymgmt_set_params() must also be present, and vice versa.

   Key Object Checking Functions
       OSSL_FUNC_keymgmt_query_operation_name() should return the name of the
       supported algorithm for the operation operation_id.  This is similar to
       provider_query_operation() (see provider-base(7)), but only works as an
       advisory.  If this function is not present, or returns NULL, the caller
       is free to assume that there's an algorithm from the same provider, of
       the same name as the one used to fetch the keymgmt and try to use that.

       OSSL_FUNC_keymgmt_has() should check whether the given keydata contains
       the subsets of data indicated by the selector.  A combination of
       several selector bits must consider all those subsets, not just one.
       An implementation is, however, free to consider an empty subset of data
       to still be a valid subset. For algorithms where some selection is not
       meaningful such as OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS for RSA keys
       the function should just return 1 as the selected subset is not really
       missing in the key.

       OSSL_FUNC_keymgmt_validate() should check if the keydata contains valid
       data subsets indicated by selection.  Some combined selections of data
       subsets may cause validation of the combined data.  For example, the
       combination of OSSL_KEYMGMT_SELECT_PRIVATE_KEY and
       OSSL_KEYMGMT_SELECT_PUBLIC_KEY (or OSSL_KEYMGMT_SELECT_KEYPAIR for
       short) is expected to check that the pairwise consistency of keydata is
       valid. The checktype parameter controls what type of check is performed
       on the subset of data. Two types of check are defined:
       OSSL_KEYMGMT_VALIDATE_FULL_CHECK and OSSL_KEYMGMT_VALIDATE_QUICK_CHECK.
       The interpretation of how much checking is performed in a full check
       versus a quick check is key type specific. Some providers may have no
       distinction between a full check and a quick check. For algorithms
       where some selection is not meaningful such as
       OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS for RSA keys the function should
       just return 1 as there is nothing to validate for that selection.

       OSSL_FUNC_keymgmt_match() should check if the data subset indicated by
       selection in keydata1 and keydata2 match.  It is assumed that the
       caller has ensured that keydata1 and keydata2 are both owned by the
       implementation of this function.

   Key Object Import, Export and Duplication Functions
       OSSL_FUNC_keymgmt_import() should import data indicated by selection
       into keydata with values taken from the OSSL_PARAM(3) array params.

       OSSL_FUNC_keymgmt_export() should extract values indicated by selection
       from keydata, create an OSSL_PARAM(3) array with them and call param_cb
       with that array as well as the given cbarg.

       OSSL_FUNC_keymgmt_import_types() should return a constant array of
       descriptor OSSL_PARAM(3) for data indicated by selection, for
       parameters that OSSL_FUNC_keymgmt_import() can handle.

       OSSL_FUNC_keymgmt_export_types() should return a constant array of
       descriptor OSSL_PARAM(3) for data indicated by selection, that the
       OSSL_FUNC_keymgmt_export() callback can expect to receive.

       OSSL_FUNC_keymgmt_dup() should duplicate data subsets indicated by
       selection or the whole key data keydata_from and create a new provider
       side key object with the data.

   Common Information Parameters
       See OSSL_PARAM(3) for further details on the parameters structure.

       Common information parameters currently recognised by all built-in
       keymgmt algorithms are as follows:

       "bits" (OSSL_PKEY_PARAM_BITS) <integer>
           The value should be the cryptographic length of the cryptosystem to
           which the key belongs, in bits.  The definition of cryptographic
           length is specific to the key cryptosystem.

       "max-size" (OSSL_PKEY_PARAM_MAX_SIZE) <integer>
           The value should be the maximum size that a caller should allocate
           to safely store a signature (called sig in provider-signature(7)),
           the result of asymmmetric encryption / decryption (out in
           provider-asym_cipher(7), a derived secret (secret in
           provider-keyexch(7), and similar data).

           Because an EVP_KEYMGMT method is always tightly bound to another
           method (signature, asymmetric cipher, key exchange, ...) and must
           be of the same provider, this number only needs to be synchronised
           with the dimensions handled in the rest of the same provider.

       "security-bits" (OSSL_PKEY_PARAM_SECURITY_BITS) <integer>
           The value should be the number of security bits of the given key.
           Bits of security is defined in SP800-57.

       "mandatory-digest" (OSSL_PKEY_PARAM_MANDATORY_DIGEST) <UTF8 string>
           If there is a mandatory digest for performing a signature operation
           with keys from this keymgmt, this parameter should get its name as
           value.

           When EVP_PKEY_get_default_digest_name() queries this parameter and
           it's filled in by the implementation, its return value will be 2.

           If the keymgmt implementation fills in the value "" or "UNDEF",
           EVP_PKEY_get_default_digest_name(3) will place the string "UNDEF"
           into its argument mdname.  This signifies that no digest should be
           specified with the corresponding signature operation.

       "default-digest" (OSSL_PKEY_PARAM_DEFAULT_DIGEST) <UTF8 string>
           If there is a default digest for performing a signature operation
           with keys from this keymgmt, this parameter should get its name as
           value.

           When EVP_PKEY_get_default_digest_name(3) queries this parameter and
           it's filled in by the implementation, its return value will be 1.
           Note that if OSSL_PKEY_PARAM_MANDATORY_DIGEST is responded to as
           well, EVP_PKEY_get_default_digest_name(3) ignores the response to
           this parameter.

           If the keymgmt implementation fills in the value "" or "UNDEF",
           EVP_PKEY_get_default_digest_name(3) will place the string "UNDEF"
           into its argument mdname.  This signifies that no digest has to be
           specified with the corresponding signature operation, but may be
           specified as an option.

RETURN VALUES
       OSSL_FUNC_keymgmt_new() and OSSL_FUNC_keymgmt_dup() should return a
       valid reference to the newly created provider side key object, or NULL
       on failure.

       OSSL_FUNC_keymgmt_import(), OSSL_FUNC_keymgmt_export(),
       OSSL_FUNC_keymgmt_get_params() and OSSL_FUNC_keymgmt_set_params()
       should return 1 for success or 0 on error.

       OSSL_FUNC_keymgmt_validate() should return 1 on successful validation,
       or 0 on failure.

       OSSL_FUNC_keymgmt_has() should return 1 if all the selected data
       subsets are contained in the given keydata or 0 otherwise.

       OSSL_FUNC_keymgmt_query_operation_name() should return a pointer to a
       string matching the requested operation, or NULL if the same name used
       to fetch the keymgmt applies.

       OSSL_FUNC_keymgmt_gettable_params() and
       OSSL_FUNC_keymgmt_settable_params() OSSL_FUNC_keymgmt_import_types(),
       OSSL_FUNC_keymgmt_export_types() should always return a constant
       OSSL_PARAM(3) array.

SEE ALSO
       provider(7), EVP_PKEY-X25519(7), EVP_PKEY-X448(7), EVP_PKEY-ED25519(7),
       EVP_PKEY-ED448(7), EVP_PKEY-EC(7), EVP_PKEY-RSA(7), EVP_PKEY-DSA(7),
       EVP_PKEY-DH(7)

HISTORY
       The KEYMGMT interface was introduced in OpenSSL 3.0.

COPYRIGHT
       Copyright 2019-2023 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
       <https://www.openssl.org/source/license.html>.



3.0.12                            2023-05-31               PROVIDER-KEYMGMT(7)