The behaviour of these functions is affected by settings in php.ini.
|openssl.cafile||""||PHP_INI_PERDIR||Available as of PHP 5.6.0.|
|openssl.capath||""||PHP_INI_PERDIR||Available as of PHP 5.6.0.|
Here's a short explanation of the configuration directives.
Location of Certificate Authority file on local filesystem which should be used with the verify_peer context option to authenticate the identity of the remote peer.
If cafile is not specified or if the certificate is not found there, the directory pointed to by capath is searched for a suitable certificate. capath must be a correctly hashed certificate directory.
See also the SSL stream context options.