## Installation

To use PHP's OpenSSL support you must also compile PHP --with-openssl[=DIR].

The OpenSSL library also has additional requirements for normal operation at run-time. Most notably, OpenSSL requires access to a random or pseudo-random number generator; on most Unix and Unix-like platforms (including Linux), this means that it must have access to a `/dev/urandom` or `/dev/random` device.

As of PHP 5.6.3, the configure option --with-system-ciphers is available which causes PHP to use the system cipher list instead of a hard-coded default.

> Note: Note to Win32 Users

> In order for this extension to work, there are DLL files that must be available to the Windows system PATH. For information on how to do this, see the FAQ entitled "How do I add my PHP directory to the PATH on Windows". Although copying DLL files from the PHP folder into the Windows system directory also works (because the system directory is by default in the system's PATH), this is not recommended. This extension requires the following files to be in the PATH: libeay32.dll, or, as of OpenSSL 1.1, libcrypto-*.dll

> Additionally, if you are planning to use the key generation and certificate signing functions, you will need to install a valid openssl.cnf file on your system. We include a sample configuration file in our win32 binary distributions, in the extras/openssl directory.

> PHP will search for the openssl.cnf using the following logic:

> - the `OPENSSL_CONF` environmental variable, if set, will be used as the path (including filename) of the configuration file.
> - the `SSLEAY_CONF` environmental variable, if set, will be used as the path (including filename) of the configuration file.
> - The file openssl.cnf will be assumed to be found in the default certificate area, as configured at the time that the openssl DLL was compiled. This is usually means that the default filename is C:\Program Files\Common Files\SSL\openssl.cnf (x64) or C:\Program Files (x86)\Common Files\SSL\openssl.cnf (x86), or, prior to PHP 7.4.0, C:\usr\local\ssl\openssl.cnf.
> In your installation, you need to decide whether to install the configuration file in the default path or whether to install it someplace else and use environmental variables (possibly on a per-virtual-host basis) to locate the configuration file. Note that it is possible to override the default path from the script using the `configargs` of the functions that require a configuration file.
> Caution

> Ensure that non-privileged users are not allowed to modify openssl.cnf.

### Changelog

Version | Description
--- | ---
7.4.0 | The OpenSSL default config path has been changed from C:\usr\local\ssl to C:\Program Files\Common Files\SSL and C:\Program Files (x86)\Common Files\SSL, respectively.