1SSL_CTX_set1_curves(3) OpenSSL SSL_CTX_set1_curves(3)
2
6 SSL_CTX_set1_curves, SSL_CTX_set1_curves_list, SSL_set1_curves,
7 SSL_set1_curves_list, SSL_get1_curves, SSL_get_shared_curve,
8 SSL_CTX_set_ecdh_auto, SSL_set_ecdh_auto - EC supported curve functions
9
11 #include <openssl/ssl.h>
12 int SSL_CTX_set1_curves(SSL_CTX *ctx, int *clist, int clistlen);
14 int SSL_CTX_set1_curves_list(SSL_CTX *ctx, char *list);
15 int SSL_set1_curves(SSL *ssl, int *clist, int clistlen);
17 int SSL_set1_curves_list(SSL *ssl, char *list);
18 int SSL_get1_curves(SSL *ssl, int *curves);
20 int SSL_get_shared_curve(SSL *s, int n);
21 int SSL_CTX_set_ecdh_auto(SSL_CTX *ctx, int onoff);
23 int SSL_set_ecdh_auto(SSL *s, int onoff);
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26 SSL_CTX_set1_curves() sets the supported curves for ctx to clistlen
27 curves in the array clist. The array consist of all NIDs of curves in
28 preference order. For a TLS client the curves are used directly in the
29 supported curves extension. For a TLS server the curves are used to
30 determine the set of shared curves.
31 SSL_CTX_set1_curves_list() sets the supported curves for ctx to string
33 list. The string is a colon separated list of curve NIDs or names, for
34 example "P-521:P-384:P-256".
35 SSL_set1_curves() and SSL_set1_curves_list() are similar except they
37 set supported curves for the SSL structure ssl.
38 SSL_get1_curves() returns the set of supported curves sent by a client
40 in the supported curves extension. It returns the total number of
41 supported curves. The curves parameter can be NULL to simply return the
42 number of curves for memory allocation purposes. The curves array is in
43 the form of a set of curve NIDs in preference order. It can return zero
44 if the client did not send a supported curves extension.
45 SSL_get_shared_curve() returns shared curve n for a server-side SSL
47 ssl. If n is -1 then the total number of shared curves is returned,
48 which may be zero. Other than for diagnostic purposes, most
49 applications will only be interested in the first shared curve so n is
50 normally set to zero. If the value n is out of range, NID_undef is
51 returned.
52 SSL_CTX_set_ecdh_auto() and SSL_set_ecdh_auto() set automatic curve
54 selection for server ctx or ssl to onoff. If onoff is 1 then the
55 highest preference curve is automatically used for ECDH temporary keys
56 used during key exchange.
57 All these functions are implemented as macros.
59
61 If an application wishes to make use of several of these functions for
62 configuration purposes either on a command line or in a file it should
63 consider using the SSL_CONF interface instead of manually parsing
64 options.
65 The functions SSL_CTX_set_ecdh_auto() and SSL_set_ecdh_auto() can be
67 used to make a server always choose the most appropriate curve for a
68 client. If set it will override any temporary ECDH parameters set by a
69 server. Previous versions of OpenSSL could effectively only use a
70 single ECDH curve set using a function such as SSL_CTX_set_ecdh_tmp().
71 Newer applications should just call:
72 SSL_CTX_set_ecdh_auto(ctx, 1);
74 and they will automatically support ECDH using the most appropriate
76 shared curve.
77
79 SSL_CTX_set1_curves(), SSL_CTX_set1_curves_list(), SSL_set1_curves(),
80 SSL_set1_curves_list(), SSL_CTX_set_ecdh_auto() and SSL_set_ecdh_auto()
81 return 1 for success and 0 for failure.
82 SSL_get1_curves() returns the number of curves, which may be zero.
84 SSL_get_shared_curve() returns the NID of shared curve n or NID_undef
86 if there is no shared curve n; or the total number of shared curves if
87 n is -1.
88 When called on a client ssl, SSL_get_shared_curve() has no meaning and
90 returns -1.
91
93 SSL_CTX_add_extra_chain_cert(3)
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96 These functions were first added to OpenSSL 1.0.2.
971.0.2o 2019-09-10 SSL_CTX_set1_curves(3)