Encrypt an S/MIME message openssl_pkcs7_decrypt openssl_pkcs7_sign OpenSSL Functions PHP Manual openssl_pkcs7_encrypt (PHP 4 >= 4.0.6, PHP 5)openssl_pkcs7_encrypt — Encrypt an S/MIME message Description bool openssl_pkcs7_encrypt ( string $infile , string $outfile , mixed $recipcerts , array $headers [, int $flags [, int $cipherid ]] ) openssl_pkcs7_encrypt() takes the contents of the file named infile and encrypts them using an RC2 40-bit cipher so that they can only be read by the intended recipients specified by recipcerts . Parameters infile outfile recipcerts Either a lone X.509 certificate, or an array of X.509 certificates. headers headers is an array of headers that will be prepended to the data after it has been encrypted. headers can be either an associative array keyed by header name, or an indexed array, where each element contains a single header line. flags flags can be used to specify options that affect the encoding process - see PKCS7 constants. cipherid Cipher can be selected with cipherid . Return Values Returns TRUE on success or FALSE on failure. ChangeLog Version Description 5.0.0 The cipherid parameter was added. Examples Example #1 openssl_pkcs7_encrypt() example <?php// the message you want to encrypt and send to your secret agent// in the field, known as nighthawk. You have his certificate// in the file nighthawk.pem$data = <<<EODNighthawk,Top secret, for your eyes only!The enemy is closing in! Meet me at the cafe at 8.30amto collect your forged passport!HQEOD;// load key$key = file_get_contents("nighthawk.pem");// save message to file$fp = fopen("msg.txt", "w");fwrite($fp, $data);fclose($fp);// encrypt itif (openssl_pkcs7_encrypt("msg.txt", "enc.txt", $key, array("To" => "nighthawk@example.com", // keyed syntax "From: HQ <hq@example.com>", // indexed syntax "Subject" => "Eyes only"))) { // message encrypted - send it! exec(ini_get("sendmail_path") . " < enc.txt");}?> openssl_pkcs7_decrypt openssl_pkcs7_sign OpenSSL Functions PHP Manual