SSL_CTX_new(3)

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, DTLS_method,
       DTLS_server_method, DTLS_client_method, DTLSv1_2_method,
       DTLSv1_2_server_method, DTLSv1_2_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 *DTLS_method(void);
        const SSL_METHOD *DTLS_server_method(void);
        const SSL_METHOD *DTLS_client_method(void);
        const SSL_METHOD *DTLSv1_2_method(void);
        const SSL_METHOD *DTLSv1_2_server_method(void);
        const SSL_METHOD *DTLSv1_2_client_method(void);
        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 sup-
           ported 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 pro-
           tocol versions, the effect is to also disable all subsequent proto-
           col 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 under-
           stand 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 under-
           stand 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 1.0.2g, EXPORT ciphers and 56-bit DES are no
           longer available with SSLv2.

       DTLS_method(), DTLS_server_method(), DTLS_client_method()
           These are the version-flexible DTLS methods.

       DTLSv1_2_method(), DTLSv1_2_server_method(), DTLSv1_2_client_method()
           These are the version-specific methods for DTLSv1.2.

       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 set-
       ting, 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.

SSL_CTX_new(3)

NAME

SYNOPSIS

DESCRIPTION

NOTES

RETURN VALUES

SEE ALSO