1SSL_CTX_new(3)                      OpenSSL                     SSL_CTX_new(3)
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NAME

6       SSL_CTX_new - create a new SSL_CTX object as framework for TLS/SSL
7       enabled functions
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SYNOPSIS

10        #include <openssl/ssl.h>
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12        SSL_CTX *SSL_CTX_new(SSL_METHOD *method);
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DESCRIPTION

15       SSL_CTX_new() creates a new SSL_CTX object as framework to establish
16       TLS/SSL enabled connections.
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NOTES

19       The SSL_CTX object uses method as connection method. The methods exist
20       in a generic type (for client and server use), a server only type, and
21       a client only type. method can be of the following types:
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23       SSLv2_method(void), SSLv2_server_method(void),
24       SSLv2_client_method(void)
25           A TLS/SSL connection established with these methods will only
26           understand the SSLv2 protocol. A client will send out SSLv2 client
27           hello messages and will also indicate that it only understand
28           SSLv2. A server will only understand SSLv2 client hello messages.
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30       SSLv3_method(void), SSLv3_server_method(void),
31       SSLv3_client_method(void)
32           A TLS/SSL connection established with these methods will only
33           understand the SSLv3 protocol. A client will send out SSLv3 client
34           hello messages and will indicate that it only understands SSLv3. A
35           server will only understand SSLv3 client hello messages. This espe‐
36           cially means, that it will not understand SSLv2 client hello mes‐
37           sages which are widely used for compatibility reasons, see
38           SSLv23_*_method().
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40       TLSv1_method(void), TLSv1_server_method(void),
41       TLSv1_client_method(void)
42           A TLS/SSL connection established with these methods will only
43           understand the TLSv1 protocol. A client will send out TLSv1 client
44           hello messages and will indicate that it only understands TLSv1. A
45           server will only understand TLSv1 client hello messages. This espe‐
46           cially means, that it will not understand SSLv2 client hello mes‐
47           sages which are widely used for compatibility reasons, see
48           SSLv23_*_method(). It will also not understand SSLv3 client hello
49           messages.
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51       SSLv23_method(void), SSLv23_server_method(void),
52       SSLv23_client_method(void)
53           A TLS/SSL connection established with these methods will understand
54           the SSLv2, SSLv3, and TLSv1 protocol. A client will send out SSLv2
55           client hello messages and will indicate that it also understands
56           SSLv3 and TLSv1. A server will understand SSLv2, SSLv3, and TLSv1
57           client hello messages. This is the best choice when compatibility
58           is a concern.
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60       The list of protocols available can later be limited using the
61       SSL_OP_NO_SSLv2, SSL_OP_NO_SSLv3, SSL_OP_NO_TLSv1 options of the
62       SSL_CTX_set_options() or SSL_set_options() functions. Using these
63       options it is possible to choose e.g. SSLv23_server_method() and be
64       able to negotiate with all possible clients, but to only allow newer
65       protocols like SSLv3 or TLSv1.
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67       SSL_CTX_new() initializes the list of ciphers, the session cache set‐
68       ting, the callbacks, the keys and certificates, and the options to its
69       default values.
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RETURN VALUES

72       The following return values can occur:
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74       NULL
75           The creation of a new SSL_CTX object failed. Check the error stack
76           to find out the reason.
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78       Pointer to an SSL_CTX object
79           The return value points to an allocated SSL_CTX object.
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SEE ALSO

82       SSL_CTX_free(3), SSL_accept(3), ssl(3),  SSL_set_connect_state(3)
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860.9.8b                            2001-07-25                    SSL_CTX_new(3)
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