To start the MySQL server so that it permits clients to connect securely, use options that identify the certificate and key files the server uses when establishing a secure connection:

For example, start the server with these lines in the my.cnf file, changing the file names as necessary:

[mysqld]
ssl-ca=ca.pem
ssl-cert=server-cert.pem
ssl-key=server-key.pem

Each option names a file in PEM format. If you have a MySQL source distribution, you can test your setup using the demonstration certificate and key files in its mysql-test/std_data directory.

The server-side --ssl option value is enabled by default.

MySQL servers compiled using OpenSSL can generate missing certificate and key files automatically at startup. See Section 6.4.6.1, “Creating SSL and RSA Certificates and Keys using MySQL”.

The server performs certificate and key file autodiscovery. If --ssl is enabled (possibly along with --ssl-cipher) and other --ssl-xxx options are not given to configure secure connections explicitly, the server attempts to enable support for secure connections automatically at startup:

If the server automatically enables support for secure connections, it writes a message to the error log. If the server discovers that the CA certificate is self-signed, it writes a warning to the error log. (The certificate will be self-signed if created automatically by the server or manually using mysql_ssl_rsa_setup.)

For any certificate and key files that the server discovers and uses automatically, it uses the file names to set the corresponding system variables (ssl_ca, ssl_cert, ssl_key).

For further control over whether clients must connect securely, use the require_secure_transport system variable; see Section 5.1.5, “Server System Variables”. For information about permitted encryption protocols and ciphers, see Section 6.4.3, “Secure Connection Protocols and Ciphers”.

For client programs, options for secure connections are similar to those used on the server side, but --ssl-cert and --ssl-key identify the client public and private key:

To connect securely to a MySQL server that supports secure connections, the options that a client must specify depend on the encryption requirements of the MySQL account used by the client. (See the discussion of the REQUIRE clause in Section 13.7.1.3, “CREATE USER Syntax”.)

Suppose that you want to connect using an account that has no special encryption requirements or was created using a CREATE USER statement that includes the REQUIRE SSL option. As a recommended set of secure-connection options, start the server with at least --ssl-cert and --ssl-key, and invoke the client with --ssl-ca. A client can connect securely like this:

shell> mysql --ssl-ca=ca.pem

To require that a client certificate also be specified, create the account using the REQUIRE X509 option. Then the client must also specify the proper client key and certificate files or the server will reject the connection:

shell> mysql --ssl-ca=ca.pem \
       --ssl-cert=client-cert.pem \
       --ssl-key=client-key.pem

To prevent use of encryption and override other --ssl-xxx options, invoke the client program with --ssl-mode=DISABLED.

shell> mysql --ssl-mode=DISABLED

Client programs attempt to establish a secure connection by default whenever the server supports secure connections:

For information about permitted encryption protocols and ciphers, see Section 6.4.3, “Secure Connection Protocols and Ciphers”.

A client can determine whether the current connection with the server uses encryption by checking the value of the Ssl_cipher status variable. If the value is empty, the connection is not encrypted. Otherwise, the connection is encrypted and the value indicates the encryption cipher. For example:

mysql> SHOW STATUS LIKE 'Ssl_cipher';
+---------------+--------------------+
| Variable_name | Value              |
+---------------+--------------------+
| Ssl_cipher    | DHE-RSA-AES256-SHA |
+---------------+--------------------+

For the mysql client, an alternative is to use the STATUS or \s command and check the SSL line:

mysql> \s
...
SSL: Cipher in use is DHE-RSA-AES256-SHA
...

Or:

mysql> \s
...
SSL: Not in use
...

The C API enables application programs to use secure connections:

Replication uses the C API, so secure connections can be used between master and slave servers. See Section 18.3.9, “Setting Up Replication to Use Secure Connections”.