5 SSL_CTX_set1_curves, SSL_CTX_set1_curves_list, SSL_set1_curves,
6 SSL_set1_curves_list, SSL_get1_curves, SSL_get_shared_curve,
7 SSL_CTX_set_ecdh_auto, SSL_set_ecdh_auto - EC supported curve functions
11 #include <openssl/ssl.h>
13 int SSL_CTX_set1_curves(SSL_CTX *ctx, int *clist, int clistlen);
14 int SSL_CTX_set1_curves_list(SSL_CTX *ctx, char *list);
16 int SSL_set1_curves(SSL *ssl, int *clist, int clistlen);
17 int SSL_set1_curves_list(SSL *ssl, char *list);
19 int SSL_get1_curves(SSL *ssl, int *curves);
20 int SSL_get_shared_curve(SSL *s, int n);
22 int SSL_CTX_set_ecdh_auto(SSL_CTX *ctx, int onoff);
23 int SSL_set_ecdh_auto(SSL *s, int onoff);
27 SSL_CTX_set1_curves() sets the supported curves for B<ctx> to B<clistlen>
28 curves in the array B<clist>. The array consist of all NIDs of curves in
29 preference order. For a TLS client the curves are used directly in the
30 supported curves extension. For a TLS server the curves are used to
31 determine the set of shared curves.
33 SSL_CTX_set1_curves_list() sets the supported curves for B<ctx> to
34 string B<list>. The string is a colon separated list of curve NIDs or
35 names, for example "P-521:P-384:P-256".
37 SSL_set1_curves() and SSL_set1_curves_list() are similar except they set
38 supported curves for the SSL structure B<ssl>.
40 SSL_get1_curves() returns the set of supported curves sent by a client
41 in the supported curves extension. It returns the total number of
42 supported curves. The B<curves> parameter can be B<NULL> to simply
43 return the number of curves for memory allocation purposes. The
44 B<curves> array is in the form of a set of curve NIDs in preference
45 order. It can return zero if the client did not send a supported curves
48 SSL_get_shared_curve() returns shared curve B<n> for a server-side
49 SSL B<ssl>. If B<n> is -1 then the total number of shared curves is
50 returned, which may be zero. Other than for diagnostic purposes,
51 most applications will only be interested in the first shared curve
52 so B<n> is normally set to zero. If the value B<n> is out of range,
53 NID_undef is returned.
55 SSL_CTX_set_ecdh_auto() and SSL_set_ecdh_auto() set automatic curve
56 selection for server B<ctx> or B<ssl> to B<onoff>. If B<onoff> is 1 then
57 the highest preference curve is automatically used for ECDH temporary
58 keys used during key exchange.
60 All these functions are implemented as macros.
64 If an application wishes to make use of several of these functions for
65 configuration purposes either on a command line or in a file it should
66 consider using the SSL_CONF interface instead of manually parsing options.
68 The functions SSL_CTX_set_ecdh_auto() and SSL_set_ecdh_auto() can be used to
69 make a server always choose the most appropriate curve for a client. If set
70 it will override any temporary ECDH parameters set by a server. Previous
71 versions of OpenSSL could effectively only use a single ECDH curve set
72 using a function such as SSL_CTX_set_ecdh_tmp(). Newer applications should
75 SSL_CTX_set_ecdh_auto(ctx, 1);
77 and they will automatically support ECDH using the most appropriate shared
82 SSL_CTX_set1_curves(), SSL_CTX_set1_curves_list(), SSL_set1_curves(),
83 SSL_set1_curves_list(), SSL_CTX_set_ecdh_auto() and SSL_set_ecdh_auto()
84 return 1 for success and 0 for failure.
86 SSL_get1_curves() returns the number of curves, which may be zero.
88 SSL_get_shared_curve() returns the NID of shared curve B<n> or NID_undef if there
89 is no shared curve B<n>; or the total number of shared curves if B<n>
92 When called on a client B<ssl>, SSL_get_shared_curve() has no meaning and
97 L<SSL_CTX_add_extra_chain_cert(3)|SSL_CTX_add_extra_chain_cert(3)>
101 These functions were first added to OpenSSL 1.0.2.