5 SSL_CTX_set1_groups, SSL_CTX_set1_groups_list, SSL_set1_groups,
6 SSL_set1_groups_list, SSL_get1_groups, SSL_get_shared_group,
7 SSL_get_negotiated_group, SSL_CTX_set1_curves, SSL_CTX_set1_curves_list,
8 SSL_set1_curves, SSL_set1_curves_list, SSL_get1_curves, SSL_get_shared_curve
9 - EC supported curve functions
13 #include <openssl/ssl.h>
15 int SSL_CTX_set1_groups(SSL_CTX *ctx, int *glist, int glistlen);
16 int SSL_CTX_set1_groups_list(SSL_CTX *ctx, char *list);
18 int SSL_set1_groups(SSL *ssl, int *glist, int glistlen);
19 int SSL_set1_groups_list(SSL *ssl, char *list);
21 int SSL_get1_groups(SSL *ssl, int *groups);
22 int SSL_get_shared_group(SSL *s, int n);
23 int SSL_get_negotiated_group(SSL *s);
25 int SSL_CTX_set1_curves(SSL_CTX *ctx, int *clist, int clistlen);
26 int SSL_CTX_set1_curves_list(SSL_CTX *ctx, char *list);
28 int SSL_set1_curves(SSL *ssl, int *clist, int clistlen);
29 int SSL_set1_curves_list(SSL *ssl, char *list);
31 int SSL_get1_curves(SSL *ssl, int *curves);
32 int SSL_get_shared_curve(SSL *s, int n);
36 For all of the functions below that set the supported groups there must be at
37 least one group in the list. A number of these functions identify groups via a
38 unique integer NID value. However support for some groups may be added by
39 external providers. In this case there will be no NID assigned for the group.
40 When setting such groups applications should use the "list" form of these
41 functions (i.e. SSL_CTX_set1_groups_list() and SSL_set1_groups_list).
43 SSL_CTX_set1_groups() sets the supported groups for B<ctx> to B<glistlen>
44 groups in the array B<glist>. The array consist of all NIDs of groups in
45 preference order. For a TLS client the groups are used directly in the
46 supported groups extension. For a TLS server the groups are used to
47 determine the set of shared groups. Currently supported groups for
48 B<TLSv1.3> are B<NID_X9_62_prime256v1>, B<NID_secp384r1>, B<NID_secp521r1>,
49 B<NID_X25519>, B<NID_X448>, B<NID_ffdhe2048>, B<NID_ffdhe3072>,
50 B<NID_ffdhe4096>, B<NID_ffdhe6144> and B<NID_ffdhe8192>.
52 SSL_CTX_set1_groups_list() sets the supported groups for B<ctx> to
53 string B<list>. The string is a colon separated list of group NIDs or
54 names, for example "P-521:P-384:P-256:X25519:ffdhe2048". Currently supported
55 groups for B<TLSv1.3> are B<P-256>, B<P-384>, B<P-521>, B<X25519>, B<X448>,
56 B<ffdhe2048>, B<ffdhe3072>, B<ffdhe4096>, B<ffdhe6144>, B<ffdhe8192>. Support
57 for other groups may be added by external providers.
59 SSL_set1_groups() and SSL_set1_groups_list() are similar except they set
60 supported groups for the SSL structure B<ssl>.
62 SSL_get1_groups() returns the set of supported groups sent by a client
63 in the supported groups extension. It returns the total number of
64 supported groups. The B<groups> parameter can be B<NULL> to simply
65 return the number of groups for memory allocation purposes. The
66 B<groups> array is in the form of a set of group NIDs in preference
67 order. It can return zero if the client did not send a supported groups
68 extension. If a supported group NID is unknown then the value is set to the
69 bitwise OR of TLSEXT_nid_unknown (0x1000000) and the id of the group.
71 SSL_get_shared_group() returns the NID of the shared group B<n> for a
72 server-side SSL B<ssl>. If B<n> is -1 then the total number of shared groups is
73 returned, which may be zero. Other than for diagnostic purposes,
74 most applications will only be interested in the first shared group
75 so B<n> is normally set to zero. If the value B<n> is out of range,
76 NID_undef is returned. If the NID for the shared group is unknown then the value
77 is set to the bitwise OR of TLSEXT_nid_unknown (0x1000000) and the id of the
80 SSL_get_negotiated_group() returns the NID of the negotiated group on a TLSv1.3
81 connection for key exchange. This can be called by either client or server. If
82 the NID for the shared group is unknown then the value is set to the bitwise OR
83 of TLSEXT_nid_unknown (0x1000000) and the id of the group.
85 All these functions are implemented as macros.
87 The curve functions are synonyms for the equivalently named group functions and
88 are identical in every respect. They exist because, prior to TLS1.3, there was
89 only the concept of supported curves. In TLS1.3 this was renamed to supported
90 groups, and extended to include Diffie Hellman groups. The group functions
91 should be used in preference.
95 If an application wishes to make use of several of these functions for
96 configuration purposes either on a command line or in a file it should
97 consider using the SSL_CONF interface instead of manually parsing options.
101 SSL_CTX_set1_groups(), SSL_CTX_set1_groups_list(), SSL_set1_groups() and
102 SSL_set1_groups_list(), return 1 for success and 0 for failure.
104 SSL_get1_groups() returns the number of groups, which may be zero.
106 SSL_get_shared_group() returns the NID of shared group B<n> or NID_undef if there
107 is no shared group B<n>; or the total number of shared groups if B<n>
110 When called on a client B<ssl>, SSL_get_shared_group() has no meaning and
113 SSL_get_negotiated_group() returns the NID of the negotiated group on a
114 TLSv1.3 connection for key exchange. Or it returns NID_undef if no negotiated
120 L<SSL_CTX_add_extra_chain_cert(3)>
124 The curve functions were added in OpenSSL 1.0.2. The equivalent group
125 functions were added in OpenSSL 1.1.1. The SSL_get_negotiated_group() function
126 was added in OpenSSL 3.0.0.
130 Copyright 2013-2020 The OpenSSL Project Authors. All Rights Reserved.
132 Licensed under the Apache License 2.0 (the "License"). You may not use
133 this file except in compliance with the License. You can obtain a copy
134 in the file LICENSE in the source distribution or at
135 L<https://www.openssl.org/source/license.html>.