De acordo com a documentação, o suporte SSL está sendo introduzido no 5.3.7.
Alterar log:
- 5.4.0 MySQL client libraries 4.1 and below are no longer supported.
- 5.3.9 Added SSL support with mysqlnd and OpenSSL.
- 5.3.7 Added SSL support with libmysqlclient and OpenSSL.
e as propriedades só estão disponíveis em 5.3.7 ou superior.
PDO::MYSQL_ATTR_SSL_CA (integer)
The file path to the SSL certificate authority.
This exists as of PHP 5.3.7.
PDO::MYSQL_ATTR_SSL_CAPATH (integer)
The file path to the directory that contains the trusted SSL CA certificates, which are stored in PEM format.
This exists as of PHP 5.3.7.
PDO::MYSQL_ATTR_SSL_CERT (integer)
The file path to the SSL certificate.
This exists as of PHP 5.3.7.
PDO::MYSQL_ATTR_SSL_CIPHER (integer)
A list of one or more permissible ciphers to use for SSL encryption, in a format understood by OpenSSL. For example: DHE-RSA-AES256-SHA:AES128-SHA
This exists as of PHP 5.3.7.
PDO::MYSQL_ATTR_SSL_KEY (integer)
The file path to the SSL key.
This exists as of PHP 5.3.7.
Veja também: link