1EVP_KEYEXCH_FREE(3ossl)             OpenSSL            EVP_KEYEXCH_FREE(3ossl)
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NAME

6       EVP_KEYEXCH_fetch, EVP_KEYEXCH_free, EVP_KEYEXCH_up_ref,
7       EVP_KEYEXCH_get0_provider, EVP_KEYEXCH_is_a,
8       EVP_KEYEXCH_do_all_provided, EVP_KEYEXCH_names_do_all,
9       EVP_KEYEXCH_get0_name, EVP_KEYEXCH_get0_description,
10       EVP_KEYEXCH_gettable_ctx_params, EVP_KEYEXCH_settable_ctx_params -
11       Functions to manage EVP_KEYEXCH algorithm objects
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SYNOPSIS

14        #include <openssl/evp.h>
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16        EVP_KEYEXCH *EVP_KEYEXCH_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
17                                       const char *properties);
18        void EVP_KEYEXCH_free(EVP_KEYEXCH *exchange);
19        int EVP_KEYEXCH_up_ref(EVP_KEYEXCH *exchange);
20        OSSL_PROVIDER *EVP_KEYEXCH_get0_provider(const EVP_KEYEXCH *exchange);
21        int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *exchange, const char *name);
22        const char *EVP_KEYEXCH_get0_name(const EVP_KEYEXCH *exchange);
23        void EVP_KEYEXCH_do_all_provided(OSSL_LIB_CTX *libctx,
24                                         void (*fn)(EVP_KEYEXCH *exchange, void *arg),
25                                         void *arg);
26        int EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *exchange,
27                                     void (*fn)(const char *name, void *data),
28                                     void *data);
29        const char *EVP_KEYEXCH_get0_description(const EVP_KEYEXCH *keyexch);
30        const OSSL_PARAM *EVP_KEYEXCH_gettable_ctx_params(const EVP_KEYEXCH *keyexch);
31        const OSSL_PARAM *EVP_KEYEXCH_settable_ctx_params(const EVP_KEYEXCH *keyexch);
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DESCRIPTION

34       EVP_KEYEXCH_fetch() fetches the key exchange implementation for the
35       given algorithm from any provider offering it, within the criteria
36       given by the properties.  See "ALGORITHM FETCHING" in crypto(7) for
37       further information.
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39       The returned value must eventually be freed with EVP_KEYEXCH_free().
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41       EVP_KEYEXCH_free() decrements the reference count for the EVP_KEYEXCH
42       structure. Typically this structure will have been obtained from an
43       earlier call to EVP_KEYEXCH_fetch(). If the reference count drops to 0
44       then the structure is freed.
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46       EVP_KEYEXCH_up_ref() increments the reference count for an EVP_KEYEXCH
47       structure.
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49       EVP_KEYEXCH_get0_provider() returns the provider that exchange was
50       fetched from.
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52       EVP_KEYEXCH_is_a() checks if exchange is an implementation of an
53       algorithm that's identifiable with name.
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55       EVP_KEYEXCH_get0_name() returns the algorithm name from the provided
56       implementation for the given exchange. Note that the exchange may have
57       multiple synonyms associated with it. In this case the first name from
58       the algorithm definition is returned. Ownership of the returned string
59       is retained by the exchange object and should not be freed by the
60       caller.
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62       EVP_KEYEXCH_names_do_all() traverses all names for the exchange, and
63       calls fn with each name and data.
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65       EVP_KEYEXCH_get0_description() returns a description of the keyexch,
66       meant for display and human consumption.  The description is at the
67       discretion of the keyexch implementation.
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69       EVP_KEYEXCH_do_all_provided() traverses all key exchange
70       implementations by all activated providers in the library context
71       libctx, and for each of the implementations, calls fn with the
72       implementation method and data as arguments.
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74       EVP_KEYEXCH_gettable_ctx_params() and EVP_KEYEXCH_settable_ctx_params()
75       return a constant OSSL_PARAM array that describes the names and types
76       of key parameters that can be retrieved or set by a key exchange
77       algorithm using EVP_PKEY_CTX_get_params(3) and
78       EVP_PKEY_CTX_set_params(3).
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RETURN VALUES

81       EVP_KEYEXCH_fetch() returns a pointer to a EVP_KEYEXCH for success or
82       NULL for failure.
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84       EVP_KEYEXCH_up_ref() returns 1 for success or 0 otherwise.
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86       EVP_KEYEXCH_names_do_all() returns 1 if the callback was called for all
87       names. A return value of 0 means that the callback was not called for
88       any names.
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90       EVP_KEYEXCH_is_a() returns 1 of exchange was identifiable, otherwise 0.
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92       EVP_KEYEXCH_gettable_ctx_params() and EVP_KEYEXCH_settable_ctx_params()
93       return a constant OSSL_PARAM array or NULL on error.
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SEE ALSO

96       "ALGORITHM FETCHING" in crypto(7), OSSL_PROVIDER(3)
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HISTORY

99       The functions described here were added in OpenSSL 3.0.
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102       Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
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104       Licensed under the Apache License 2.0 (the "License").  You may not use
105       this file except in compliance with the License.  You can obtain a copy
106       in the file LICENSE in the source distribution or at
107       <https://www.openssl.org/source/license.html>.
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1113.0.5                             2022-11-01           EVP_KEYEXCH_FREE(3ossl)
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