(PHP 4 >= 4.0.6, PHP 5, PHP 7)
openssl_pkcs7_sign — Sign an S/MIME message
openssl_pkcs7_sign ( string $infilename , string $outfilename , mixed $signcert , mixed $privkey , array $headers [, int $flags = PKCS7_DETACHED [, string $extracerts ]] ) : bool
openssl_pkcs7_sign() takes the contents of the file named infilename and signs them using the certificate and its matching private key specified by signcert and privkey parameters.
infilename
The input file you are intending to digitally sign.
outfilename
The file which the digital signature will be written to.
signcert
The X.509 certificate used to digitally sign infilename. See Key/Certificate parameters for a list of valid values.
privkey
privkey is the private key corresponding to signcert. See Public/Private Key parameters for a list of valid values.
headers
headers is an array of headers that will be prepended to the data after it has been signed (see openssl_pkcs7_encrypt() for more information about the format of this parameter).
flags
flags can be used to alter the output - see PKCS7 constants.
extracerts
extracerts specifies the name of a file containing a bunch of extra certificates to include in the signature which can for example be used to help the recipient to verify the certificate that you used.
Returns true on success or false on failure.
Example #1 openssl_pkcs7_sign() example
<?php
// the message you want to sign so that recipient can be sure it was you that
// sent it
$data = <<<EOD
You have my authorization to spend $10,000 on dinner expenses.
The CEO
EOD;
// save message to file
$fp = fopen("msg.txt", "w");
fwrite($fp, $data);
fclose($fp);
// encrypt it
if (openssl_pkcs7_sign("msg.txt", "signed.txt", "file://mycert.pem",
array("file://mycert.pem", "mypassphrase"),
array("To" => "[email protected]", // keyed syntax
"From: HQ <[email protected]>", // indexed syntax
"Subject" => "Eyes only")
)) {
// message signed - send it!
exec(ini_get("sendmail_path") . " < signed.txt");
}
?>
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https://www.php.net/manual/en/function.openssl-pkcs7-sign.php