Is it possible to read SSL information in PHP from any website?

Question

I want to know is it possible to read information from other parties using PHP about their SSL certificate information, I've tried to find about it for ages but there's no real answer that has been found for me.

For example, I input "www.paypal.com" into the script and it will return the following:

• Authority: VeriSign, Inc
• Expires: 18th February 2011 (18/02/11)
• Type: Extended Validation
• Host: www.paypal.com
• MD5: a8e7o7a8e9e9
• SHA1: c2a4a1e4e3a2

And, whatever else is possible to obtain. I would like the script in PHP please.

Answer 1

<?php
$g = stream_context_create (array("ssl" => array("capture_peer_cert" => true)));
$r = stream_socket_client("ssl://www.google.com:443", $errno, $errstr, 30,
    STREAM_CLIENT_CONNECT, $g);
$cont = stream_context_get_params($r);
print_r( openssl_x509_parse($cont["options"]["ssl"]["peer_certificate"]) );
?>

Answer 2

I have written a PHP class for getting SSL information:

class SSL {

    public $domain, $validFrom, $validTo, $issuer, $validity, $validitytot, $crtValRemaining;

    private static function instantiate($url, $info) {
        $obj = new static;
        $obj->domain = $url;
        $obj->validFrom = $info['validFrom'];
        $obj->validTo = $info['validTo'];
        $obj->issuer = $info['issuer'];
        $obj->validity = $info['validity'];
        $obj->validitytot = $info['validitytot'];
        $obj->crtValRemaining = $info['crtValRemaining'];

        return $obj;
    }

    public static function getSSLinfo($url) {
        $ssl_info = [];
        $certinfo = static::getCertificateDetails($url);
        $validFrom_time_t_m = static::dateFormatMonth($certinfo['validFrom_time_t']);
        $validTo_time_t_m = static::dateFormatMonth($certinfo['validTo_time_t']);

        $validFrom_time_t = static::dateFormat($certinfo['validFrom_time_t']);
        $validTo_time_t = static::dateFormat($certinfo['validTo_time_t']);
        $current_t = static::dateFormat(time());

        $ssl_info['validFrom'] = $validFrom_time_t_m;
        $ssl_info['validTo'] = $validTo_time_t_m;
        $ssl_info['issuer'] = $certinfo['issuer']['O'];

        $ssl_info['validity'] = static::diffDate($current_t, $validTo_time_t)." days";
        $ssl_info['validitytot'] = (static::diffDate($validFrom_time_t, $validTo_time_t)-1).' days';

        $ssl_info['crtValRemaining'] =$certinfo['validTo_time_t'];

        return static::instantiate($url, $ssl_info); // return an object
    }

    private static function getCertificateDetails($url) {
        $urlStr = strtolower(trim($url)); 

        $parsed = parse_url($urlStr);// add http://
        if (empty($parsed['scheme'])) {
            $urlStr = 'http://' . ltrim($urlStr, '/');
        }
        $orignal_parse = parse_url($urlStr, PHP_URL_HOST);
        $get = stream_context_create(array("ssl" => array("capture_peer_cert" => TRUE)));
        $read = stream_socket_client("ssl://".$orignal_parse.":443", $errno, $errstr, 30, STREAM_CLIENT_CONNECT, $get);
        $cert = stream_context_get_params($read);
        $certinfo = openssl_x509_parse($cert['options']['ssl']['peer_certificate']);
        return $certinfo;
    }

    private static function dateFormat($stamp) {
        return  strftime("%Y-%m-%d", $stamp);
    }

    private static function dateFormatMonth($stamp) {
        return  strftime("%Y-%b-%d", $stamp);
    }

    private static function diffDate($from, $to) {
        $date1=date_create($from);
        $date2=date_create($to);
        $diff=date_diff($date1,$date2);
        return ltrim($diff->format("%R%a"), "+");
    }

}

EX:

$certInfo = SSL::getSSLinfo('stackoverflow.com'); 
echo $certInfo->validFrom .'<br>';
echo $certInfo->validTo .'<br>';
echo $certInfo->issuer .'<br>';
echo $certInfo->validity .'<br>';
echo $certInfo->validitytot .'<br>';
echo $certInfo->crtValRemaining .'<br>';

[Make sure you understand the "instantiate" method inside SSL class]. Thank you...