| 1 | =pod
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| 2 |
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| 3 | =head1 NAME
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| 4 |
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| 5 | EVP_KEYEXCH_fetch, EVP_KEYEXCH_free, EVP_KEYEXCH_up_ref,
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| 6 | EVP_KEYEXCH_get0_provider, EVP_KEYEXCH_is_a, EVP_KEYEXCH_do_all_provided,
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| 7 | EVP_KEYEXCH_names_do_all, EVP_KEYEXCH_get0_name, EVP_KEYEXCH_get0_description,
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| 8 | EVP_KEYEXCH_gettable_ctx_params, EVP_KEYEXCH_settable_ctx_params
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| 9 | - Functions to manage EVP_KEYEXCH algorithm objects
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| 10 |
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| 11 | =head1 SYNOPSIS
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| 12 |
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| 13 | #include <openssl/evp.h>
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| 14 |
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| 15 | EVP_KEYEXCH *EVP_KEYEXCH_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
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| 16 | const char *properties);
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| 17 | void EVP_KEYEXCH_free(EVP_KEYEXCH *exchange);
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| 18 | int EVP_KEYEXCH_up_ref(EVP_KEYEXCH *exchange);
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| 19 | OSSL_PROVIDER *EVP_KEYEXCH_get0_provider(const EVP_KEYEXCH *exchange);
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| 20 | int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *exchange, const char *name);
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| 21 | const char *EVP_KEYEXCH_get0_name(const EVP_KEYEXCH *exchange);
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| 22 | void EVP_KEYEXCH_do_all_provided(OSSL_LIB_CTX *libctx,
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| 23 | void (*fn)(EVP_KEYEXCH *exchange, void *arg),
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| 24 | void *arg);
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| 25 | int EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *exchange,
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| 26 | void (*fn)(const char *name, void *data),
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| 27 | void *data);
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| 28 | const char *EVP_KEYEXCH_get0_description(const EVP_KEYEXCH *keyexch);
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| 29 | const OSSL_PARAM *EVP_KEYEXCH_gettable_ctx_params(const EVP_KEYEXCH *keyexch);
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| 30 | const OSSL_PARAM *EVP_KEYEXCH_settable_ctx_params(const EVP_KEYEXCH *keyexch);
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| 31 |
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| 32 | =head1 DESCRIPTION
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| 33 |
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| 34 | EVP_KEYEXCH_fetch() fetches the key exchange implementation for the given
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| 35 | I<algorithm> from any provider offering it, within the criteria given
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| 36 | by the I<properties>.
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| 37 | See L<crypto(7)/ALGORITHM FETCHING> for further information.
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| 38 |
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| 39 | The returned value must eventually be freed with EVP_KEYEXCH_free().
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| 40 |
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| 41 | EVP_KEYEXCH_free() decrements the reference count for the B<EVP_KEYEXCH>
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| 42 | structure. Typically this structure will have been obtained from an earlier call
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| 43 | to EVP_KEYEXCH_fetch(). If the reference count drops to 0 then the
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| 44 | structure is freed.
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| 45 |
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| 46 | EVP_KEYEXCH_up_ref() increments the reference count for an B<EVP_KEYEXCH>
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| 47 | structure.
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| 48 |
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| 49 | EVP_KEYEXCH_get0_provider() returns the provider that I<exchange> was
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| 50 | fetched from.
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| 51 |
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| 52 | EVP_KEYEXCH_is_a() checks if I<exchange> is an implementation of an
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| 53 | algorithm that's identifiable with I<name>.
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| 54 |
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| 55 | EVP_KEYEXCH_get0_name() returns the algorithm name from the provided
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| 56 | implementation for the given I<exchange>. Note that the I<exchange> may have
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| 57 | multiple synonyms associated with it. In this case the first name from the
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| 58 | algorithm definition is returned. Ownership of the returned string is retained
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| 59 | by the I<exchange> object and should not be freed by the caller.
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| 60 |
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| 61 | EVP_KEYEXCH_names_do_all() traverses all names for the I<exchange>, and
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| 62 | calls I<fn> with each name and I<data>.
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| 63 |
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| 64 | EVP_KEYEXCH_get0_description() returns a description of the I<keyexch>, meant
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| 65 | for display and human consumption. The description is at the discretion of
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| 66 | the I<keyexch> implementation.
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| 67 |
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| 68 | EVP_KEYEXCH_do_all_provided() traverses all key exchange implementations by
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| 69 | all activated providers in the library context I<libctx>, and for each
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| 70 | of the implementations, calls I<fn> with the implementation method and
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| 71 | I<data> as arguments.
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| 72 |
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| 73 | EVP_KEYEXCH_gettable_ctx_params() and EVP_KEYEXCH_settable_ctx_params() return
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| 74 | a constant L<OSSL_PARAM(3)> array that describes the names and types of key
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| 75 | parameters that can be retrieved or set by a key exchange algorithm using
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| 76 | L<EVP_PKEY_CTX_get_params(3)> and L<EVP_PKEY_CTX_set_params(3)>.
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| 77 |
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| 78 | =head1 RETURN VALUES
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| 79 |
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| 80 | EVP_KEYEXCH_fetch() returns a pointer to a B<EVP_KEYEXCH> for success
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| 81 | or NULL for failure.
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| 82 |
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| 83 | EVP_KEYEXCH_up_ref() returns 1 for success or 0 otherwise.
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| 84 |
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| 85 | EVP_KEYEXCH_names_do_all() returns 1 if the callback was called for all
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| 86 | names. A return value of 0 means that the callback was not called for any names.
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| 87 |
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| 88 | EVP_KEYEXCH_is_a() returns 1 of I<exchange> was identifiable,
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| 89 | otherwise 0.
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| 90 |
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| 91 | EVP_KEYEXCH_gettable_ctx_params() and EVP_KEYEXCH_settable_ctx_params() return
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| 92 | a constant L<OSSL_PARAM(3)> array or NULL on error.
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| 93 |
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| 94 | =head1 SEE ALSO
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| 95 |
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| 96 | L<crypto(7)/ALGORITHM FETCHING>, L<OSSL_PROVIDER(3)>
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| 97 |
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| 98 | =head1 HISTORY
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| 99 |
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| 100 | The functions described here were added in OpenSSL 3.0.
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| 101 |
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| 102 | =head1 COPYRIGHT
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| 103 |
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| 104 | Copyright 2019-2022 The OpenSSL Project Authors. All Rights Reserved.
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| 105 |
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| 106 | Licensed under the Apache License 2.0 (the "License"). You may not use
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| 107 | this file except in compliance with the License. You can obtain a copy
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| 108 | in the file LICENSE in the source distribution or at
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| 109 | L<https://www.openssl.org/source/license.html>.
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| 110 |
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| 111 | =cut
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