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EVP_ASYM_CIPHER_free(3)             OpenSSL            EVP_ASYM_CIPHER_free(3)



NAME
       EVP_ASYM_CIPHER_fetch, EVP_ASYM_CIPHER_free, EVP_ASYM_CIPHER_up_ref,
       EVP_ASYM_CIPHER_is_a, EVP_ASYM_CIPHER_get0_provider,
       EVP_ASYM_CIPHER_do_all_provided, EVP_ASYM_CIPHER_names_do_all,
       EVP_ASYM_CIPHER_get0_name, EVP_ASYM_CIPHER_get0_description,
       EVP_ASYM_CIPHER_gettable_ctx_params,
       EVP_ASYM_CIPHER_settable_ctx_params - Functions to manage
       EVP_ASYM_CIPHER algorithm objects

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/evp.h>

        EVP_ASYM_CIPHER *EVP_ASYM_CIPHER_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
                                               const char *properties);
        void EVP_ASYM_CIPHER_free(EVP_ASYM_CIPHER *cipher);
        int EVP_ASYM_CIPHER_up_ref(EVP_ASYM_CIPHER *cipher);
        const char *EVP_ASYM_CIPHER_get0_name(const EVP_ASYM_CIPHER *cipher);
        int EVP_ASYM_CIPHER_is_a(const EVP_ASYM_CIPHER *cipher, const char *name);
        OSSL_PROVIDER *EVP_ASYM_CIPHER_get0_provider(const EVP_ASYM_CIPHER *cipher);
        void EVP_ASYM_CIPHER_do_all_provided(OSSL_LIB_CTX *libctx,
                                             void (*fn)(EVP_ASYM_CIPHER *cipher,
                                                        void *arg),
                                             void *arg);
        int EVP_ASYM_CIPHER_names_do_all(const EVP_ASYM_CIPHER *cipher,
                                         void (*fn)(const char *name, void *data),
                                         void *data);
        const char *EVP_ASYM_CIPHER_get0_description(const EVP_ASYM_CIPHER *cipher);
        const OSSL_PARAM *EVP_ASYM_CIPHER_gettable_ctx_params(const EVP_ASYM_CIPHER *cip);
        const OSSL_PARAM *EVP_ASYM_CIPHER_settable_ctx_params(const EVP_ASYM_CIPHER *cip);

DESCRIPTION
       EVP_ASYM_CIPHER_fetch() fetches the implementation for the given
       algorithm from any provider offering it, within the criteria given by
       the properties and in the scope of the given library context ctx (see
       OSSL_LIB_CTX(3)). The algorithm will be one offering functions for
       performing asymmetric cipher related tasks such as asymmetric
       encryption and decryption.  See "ALGORITHM FETCHING" in crypto(7) for
       further information.

       The returned value must eventually be freed with
       EVP_ASYM_CIPHER_free().

       EVP_ASYM_CIPHER_free() decrements the reference count for the
       EVP_ASYM_CIPHER structure. Typically this structure will have been
       obtained from an earlier call to EVP_ASYM_CIPHER_fetch(). If the
       reference count drops to 0 then the structure is freed.

       EVP_ASYM_CIPHER_up_ref() increments the reference count for an
       EVP_ASYM_CIPHER structure.

       EVP_ASYM_CIPHER_is_a() returns 1 if cipher is an implementation of an
       algorithm that's identifiable with name, otherwise 0.

       EVP_ASYM_CIPHER_get0_provider() returns the provider that cipher was
       fetched from.

       EVP_ASYM_CIPHER_do_all_provided() traverses all EVP_ASYM_CIPHERs
       implemented by all activated providers in the given library context
       libctx, and for each of the implementations, calls the given function
       fn with the implementation method and the given arg as argument.

       EVP_ASYM_CIPHER_get0_name() returns the algorithm name from the
       provided implementation for the given cipher. Note that the cipher may
       have multiple synonyms associated with it. In this case the first name
       from the algorithm definition is returned. Ownership of the returned
       string is retained by the cipher object and should not be freed by the
       caller.

       EVP_ASYM_CIPHER_names_do_all() traverses all names for cipher, and
       calls fn with each name and data.

       EVP_ASYM_CIPHER_get0_description() returns a description of the cipher,
       meant for display and human consumption.  The description is at the
       discretion of the cipher implementation.

       EVP_ASYM_CIPHER_gettable_ctx_params() and
       EVP_ASYM_CIPHER_settable_ctx_params() return a constant OSSL_PARAM(3)
       array that describes the names and types of key parameters that can be
       retrieved or set by a key encryption algorithm using
       EVP_PKEY_CTX_get_params(3) and EVP_PKEY_CTX_set_params(3).

RETURN VALUES
       EVP_ASYM_CIPHER_fetch() returns a pointer to an EVP_ASYM_CIPHER for
       success or NULL for failure.

       EVP_ASYM_CIPHER_up_ref() returns 1 for success or 0 otherwise.

       EVP_ASYM_CIPHER_names_do_all() returns 1 if the callback was called for
       all names. A return value of 0 means that the callback was not called
       for any names.

       EVP_ASYM_CIPHER_gettable_ctx_params() and
       EVP_ASYM_CIPHER_settable_ctx_params() return a constant OSSL_PARAM(3)
       array or NULL on error.

SEE ALSO
       "ALGORITHM FETCHING" in crypto(7), OSSL_PROVIDER(3)

HISTORY
       The functions described here were added in OpenSSL 3.0.

COPYRIGHT
       Copyright 2019-2021 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                            2023-05-07           EVP_ASYM_CIPHER_free(3)