SSL_CTX_new(3) OpenSSL SSL_CTX_new(3)NAMESSL_CTX_new - create a new SSL_CTX object as framework for TLS/SSL
enabled functions
SYNOPSIS
#include <openssl/ssl.h>
SSL_CTX *SSL_CTX_new(SSL_METHOD *method);
DESCRIPTIONSSL_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:
SSLv2_method(void), SSLv2_server_method(void),
SSLv2_client_method(void)
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.
SSLv3_method(void), SSLv3_server_method(void),
SSLv3_client_method(void)
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. This espe‐
cially means, that it will not understand SSLv2 client hello mes‐
sages which are widely used for compatibility reasons, see
SSLv23_*_method().
TLSv1_method(void), TLSv1_server_method(void),
TLSv1_client_method(void)
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. This espe‐
cially means, that it will not understand SSLv2 client hello mes‐
sages which are widely used for compatibility reasons, see
SSLv23_*_method(). It will also not understand SSLv3 client hello
messages.
SSLv23_method(void), SSLv23_server_method(void),
SSLv23_client_method(void)
A TLS/SSL connection established with these methods will understand
the SSLv2, SSLv3, and TLSv1 protocol. A client will send out SSLv2
client hello messages and will indicate that it also understands
SSLv3 and TLSv1. A server will understand SSLv2, SSLv3, and TLSv1
client hello messages. This is the best choice when compatibility
is a concern.
The list of protocols available can later be limited using the
SSL_OP_NO_SSLv2, SSL_OP_NO_SSLv3, SSL_OP_NO_TLSv1 options of the
SSL_CTX_set_options() or SSL_set_options() functions. Using these
options it is possible to choose e.g. SSLv23_server_method() and be
able to negotiate with all possible clients, but to only allow newer
protocols like SSLv3 or TLSv1.
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.
SEE ALSOSSL_CTX_free(3), SSL_accept(3), ssl(3), SSL_set_connect_state(3)0.9.7d 2002-12-01 SSL_CTX_new(3)