1=pod
2
3=head1 NAME
4
5EVP_ASYM_CIPHER_fetch, EVP_ASYM_CIPHER_free, EVP_ASYM_CIPHER_up_ref,
6EVP_ASYM_CIPHER_is_a, EVP_ASYM_CIPHER_get0_provider,
7EVP_ASYM_CIPHER_do_all_provided, EVP_ASYM_CIPHER_names_do_all,
8EVP_ASYM_CIPHER_get0_name, EVP_ASYM_CIPHER_get0_description,
9EVP_ASYM_CIPHER_gettable_ctx_params, EVP_ASYM_CIPHER_settable_ctx_params
10- Functions to manage EVP_ASYM_CIPHER algorithm objects
11
12=head1 SYNOPSIS
13
14 #include <openssl/evp.h>
15
16 EVP_ASYM_CIPHER *EVP_ASYM_CIPHER_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
17                                        const char *properties);
18 void EVP_ASYM_CIPHER_free(EVP_ASYM_CIPHER *cipher);
19 int EVP_ASYM_CIPHER_up_ref(EVP_ASYM_CIPHER *cipher);
20 const char *EVP_ASYM_CIPHER_get0_name(const EVP_ASYM_CIPHER *cipher);
21 int EVP_ASYM_CIPHER_is_a(const EVP_ASYM_CIPHER *cipher, const char *name);
22 OSSL_PROVIDER *EVP_ASYM_CIPHER_get0_provider(const EVP_ASYM_CIPHER *cipher);
23 void EVP_ASYM_CIPHER_do_all_provided(OSSL_LIB_CTX *libctx,
24                                      void (*fn)(EVP_ASYM_CIPHER *cipher,
25                                                 void *arg),
26                                      void *arg);
27 int EVP_ASYM_CIPHER_names_do_all(const EVP_ASYM_CIPHER *cipher,
28                                  void (*fn)(const char *name, void *data),
29                                  void *data);
30 const char *EVP_ASYM_CIPHER_get0_description(const EVP_ASYM_CIPHER *cipher);
31 const OSSL_PARAM *EVP_ASYM_CIPHER_gettable_ctx_params(const EVP_ASYM_CIPHER *cip);
32 const OSSL_PARAM *EVP_ASYM_CIPHER_settable_ctx_params(const EVP_ASYM_CIPHER *cip);
33
34=head1 DESCRIPTION
35
36EVP_ASYM_CIPHER_fetch() fetches the implementation for the given
37B<algorithm> from any provider offering it, within the criteria given
38by the B<properties> and in the scope of the given library context B<ctx> (see
39L<OSSL_LIB_CTX(3)>). The algorithm will be one offering functions for performing
40asymmetric cipher related tasks such as asymmetric encryption and decryption.
41See L<crypto(7)/ALGORITHM FETCHING> for further information.
42
43The returned value must eventually be freed with EVP_ASYM_CIPHER_free().
44
45EVP_ASYM_CIPHER_free() decrements the reference count for the B<EVP_ASYM_CIPHER>
46structure. Typically this structure will have been obtained from an earlier call
47to EVP_ASYM_CIPHER_fetch(). If the reference count drops to 0 then the
48structure is freed.
49
50EVP_ASYM_CIPHER_up_ref() increments the reference count for an
51B<EVP_ASYM_CIPHER> structure.
52
53EVP_ASYM_CIPHER_is_a() returns 1 if I<cipher> is an implementation of an
54algorithm that's identifiable with I<name>, otherwise 0.
55
56EVP_ASYM_CIPHER_get0_provider() returns the provider that I<cipher> was
57fetched from.
58
59EVP_ASYM_CIPHER_do_all_provided() traverses all EVP_ASYM_CIPHERs implemented by
60all activated providers in the given library context I<libctx>, and for each of
61the implementations, calls the given function I<fn> with the implementation
62method and the given I<arg> as argument.
63
64EVP_ASYM_CIPHER_get0_name() returns the algorithm name from the provided
65implementation for the given I<cipher>. Note that the I<cipher> may have
66multiple synonyms associated with it. In this case the first name from the
67algorithm definition is returned. Ownership of the returned string is retained
68by the I<cipher> object and should not be freed by the caller.
69
70EVP_ASYM_CIPHER_names_do_all() traverses all names for I<cipher>, and calls
71I<fn> with each name and I<data>.
72
73EVP_ASYM_CIPHER_get0_description() returns a description of the I<cipher>,
74meant for display and human consumption.  The description is at the
75discretion of the I<cipher> implementation.
76
77EVP_ASYM_CIPHER_gettable_ctx_params() and EVP_ASYM_CIPHER_settable_ctx_params()
78return a constant L<OSSL_PARAM(3)> array that describes the names and types of key
79parameters that can be retrieved or set by a key encryption algorithm using
80L<EVP_PKEY_CTX_get_params(3)> and L<EVP_PKEY_CTX_set_params(3)>.
81
82=head1 RETURN VALUES
83
84EVP_ASYM_CIPHER_fetch() returns a pointer to an B<EVP_ASYM_CIPHER> for success
85or B<NULL> for failure.
86
87EVP_ASYM_CIPHER_up_ref() returns 1 for success or 0 otherwise.
88
89EVP_ASYM_CIPHER_names_do_all() returns 1 if the callback was called for all
90names. A return value of 0 means that the callback was not called for any names.
91
92EVP_ASYM_CIPHER_gettable_ctx_params() and EVP_ASYM_CIPHER_settable_ctx_params()
93return a constant L<OSSL_PARAM(3)> array or NULL on error.
94
95=head1 SEE ALSO
96
97L<crypto(7)/ALGORITHM FETCHING>, L<OSSL_PROVIDER(3)>
98
99=head1 HISTORY
100
101The functions described here were added in OpenSSL 3.0.
102
103=head1 COPYRIGHT
104
105Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
106
107Licensed under the Apache License 2.0 (the "License").  You may not use
108this file except in compliance with the License.  You can obtain a copy
109in the file LICENSE in the source distribution or at
110L<https://www.openssl.org/source/license.html>.
111
112=cut
113