SSL_CTX_new(3SSL)                            OpenSSL                            SSL_CTX_new(3SSL)



NAME
       SSL_CTX_new, SSLv23_method, SSLv23_server_method, SSLv23_client_method, TLSv1_2_method,
       TLSv1_2_server_method, TLSv1_2_client_method, TLSv1_1_method, TLSv1_1_server_method,
       TLSv1_1_client_method, TLSv1_method, TLSv1_server_method, TLSv1_client_method,
       SSLv3_method, SSLv3_server_method, SSLv3_client_method, SSLv2_method, SSLv2_server_method,
       SSLv2_client_method, DTLSv1_method, DTLSv1_server_method, DTLSv1_client_method - create a
       new SSL_CTX object as framework for TLS/SSL enabled functions

SYNOPSIS
        #include <openssl/ssl.h>

        SSL_CTX *SSL_CTX_new(const SSL_METHOD *method);
        const SSL_METHOD *SSLv23_method(void);
        const SSL_METHOD *SSLv23_server_method(void);
        const SSL_METHOD *SSLv23_client_method(void);
        const SSL_METHOD *TLSv1_2_method(void);
        const SSL_METHOD *TLSv1_2_server_method(void);
        const SSL_METHOD *TLSv1_2_client_method(void);
        const SSL_METHOD *TLSv1_1_method(void);
        const SSL_METHOD *TLSv1_1_server_method(void);
        const SSL_METHOD *TLSv1_1_client_method(void);
        const SSL_METHOD *TLSv1_method(void);
        const SSL_METHOD *TLSv1_server_method(void);
        const SSL_METHOD *TLSv1_client_method(void);
        #ifndef OPENSSL_NO_SSL3_METHOD
        const SSL_METHOD *SSLv3_method(void);
        const SSL_METHOD *SSLv3_server_method(void);
        const SSL_METHOD *SSLv3_client_method(void);
        #endif
        #ifndef OPENSSL_NO_SSL2
        const SSL_METHOD *SSLv2_method(void);
        const SSL_METHOD *SSLv2_server_method(void);
        const SSL_METHOD *SSLv2_client_method(void);
        #endif

        const SSL_METHOD *DTLSv1_method(void);
        const SSL_METHOD *DTLSv1_server_method(void);
        const SSL_METHOD *DTLSv1_client_method(void);

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

NOTES
       The SSL_CTX object uses method as connection method. The methods exist in a generic type
       (for client and server use), a server only type, and a client only type. method can be of
       the following types:

       SSLv23_method(), SSLv23_server_method(), SSLv23_client_method()
           These are the general-purpose version-flexible SSL/TLS methods.  The actual protocol
           version used will be negotiated to the highest version mutually supported by the
           client and the server.  The supported protocols are SSLv2, SSLv3, TLSv1, TLSv1.1 and
           TLSv1.2.  Most applications should use these method, and avoid the version specific
           methods described below.

           The list of protocols available can be further limited using the SSL_OP_NO_SSLv2,
           SSL_OP_NO_SSLv3, SSL_OP_NO_TLSv1, SSL_OP_NO_TLSv1_1 and SSL_OP_NO_TLSv1_2 options of
           the SSL_CTX_set_options(3) or SSL_set_options(3) functions.  Clients should avoid
           creating "holes" in the set of protocols they support, when disabling a protocol, make
           sure that you also disable either all previous or all subsequent protocol versions.
           In clients, when a protocol version is disabled without disabling all previous
           protocol versions, the effect is to also disable all subsequent protocol versions.

           The SSLv2 and SSLv3 protocols are deprecated and should generally not be used.
           Applications should typically use SSL_CTX_set_options(3) in combination with the
           SSL_OP_NO_SSLv3 flag to disable negotiation of SSLv3 via the above version-flexible
           SSL/TLS methods.  The SSL_OP_NO_SSLv2 option is set by default, and would need to be
           cleared via SSL_CTX_clear_options(3) in order to enable negotiation of SSLv2.

       TLSv1_2_method(), TLSv1_2_server_method(), TLSv1_2_client_method()
           A TLS/SSL connection established with these methods will only understand the TLSv1.2
           protocol.  A client will send out TLSv1.2 client hello messages and will also indicate
           that it only understand TLSv1.2.  A server will only understand TLSv1.2 client hello
           messages.

       TLSv1_1_method(), TLSv1_1_server_method(), TLSv1_1_client_method()
           A TLS/SSL connection established with these methods will only understand the TLSv1.1
           protocol.  A client will send out TLSv1.1 client hello messages and will also indicate
           that it only understand TLSv1.1.  A server will only understand TLSv1.1 client hello
           messages.

       TLSv1_method(), TLSv1_server_method(), TLSv1_client_method()
           A TLS/SSL connection established with these methods will only understand the TLSv1
           protocol.  A client will send out TLSv1 client hello messages and will indicate that
           it only understands TLSv1.  A server will only understand TLSv1 client hello messages.

       SSLv3_method(), SSLv3_server_method(), SSLv3_client_method()
           A TLS/SSL connection established with these methods will only understand the SSLv3
           protocol.  A client will send out SSLv3 client hello messages and will indicate that
           it only understands SSLv3.  A server will only understand SSLv3 client hello messages.
           The SSLv3 protocol is deprecated and should not be used.

       SSLv2_method(), SSLv2_server_method(), SSLv2_client_method()
           A TLS/SSL connection established with these methods will only understand the SSLv2
           protocol.  A client will send out SSLv2 client hello messages and will also indicate
           that it only understand SSLv2.  A server will only understand SSLv2 client hello
           messages.  The SSLv2 protocol offers little to no security and should not be used.  As
           of OpenSSL 1.0.1s, EXPORT ciphers and 56-bit DES are no longer available with SSLv2.

       DTLSv1_method(), DTLSv1_server_method(), DTLSv1_client_method()
           These are the version-specific methods for DTLSv1.

       SSL_CTX_new() initializes the list of ciphers, the session cache setting, the callbacks,
       the keys and certificates and the options to its default values.

RETURN VALUES
       The following return values can occur:

       NULL
           The creation of a new SSL_CTX object failed. Check the error stack to find out the
           reason.

       Pointer to an SSL_CTX object
           The return value points to an allocated SSL_CTX object.

SEE ALSO
       SSL_CTX_set_options(3), SSL_CTX_clear_options(3), SSL_set_options(3), SSL_CTX_free(3),
       SSL_accept(3), ssl(3),  SSL_set_connect_state(3)



1.0.1t                                      2016-05-03                          SSL_CTX_new(3SSL)