openssl_spki_verify

(PHP 5 >= 5.6.0, PHP 7, PHP 8)

openssl_spki_verify — Verifies a signed public key and challenge

Description

openssl_spki_verify(string $spki): bool

Validates the supplied signed public key and challenge

Parameters

spki: Expects a valid signed public key and challenge

Return Values

Returns true on success or false on failure.

Errors/Exceptions

Emits an E_WARNING level error if an invalid argument is passed via the spki parameter.

Examples

Example #1 openssl_spki_verify() example

Validates an existing signed public key and challenge

<?php
$pkey = openssl_pkey_new('secret password');
$spkac = openssl_spki_new($pkey, 'challenge string');

if (openssl_spki_verify(preg_replace('/SPKAC=/', '', $spkac))) {
    echo $spkac;
} else {
    echo "SPKAC validation failed";
}
?>

Example #2 openssl_spki_verify() example from <keygen>

Validates an existing signed public key and challenge issued from the <keygen> element

<?php
if (openssl_spki_verify(preg_replace('/SPKAC=/', '', $_POST['spkac']))) {
    echo $spkac;
} else {
    echo "SPKAC validation failed";
}
?>
<keygen name="spkac" challenge="challenge string" keytype="RSA">

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User Contributed Notes 2 notes

down

carloshlfzanon at gmail dot com ¶

7 years ago

This openssl_spki_* funcs are very usefull to use with <keygen/> tag in html5.

Example:

<?php
session_start();

// form submitted... (?)
if(isset($_POST['security']))
{
    // If true, the send from <keygen/> is valid and you can
    // test the challenge too
    if(openssl_spki_verify($_POST['security']))
    {
        // Gets challenge string
        $challenge = openssl_spki_export_challenge($_POST['security']);

        // If true... you are not trying to trick it.
        // If user open 2 windows to prevent data lost from a "mistake" or him just press "back" button
        //  and re-send last data... you can handle it using something like it.
        if($challenge == $_SESSION['lastForm'])
        {
            echo 'Ok, this one is valid.', '<br><br>';
        }
        else
        {
            echo 'Nice try... nice try...', '<br><br>'; 
        }
    }

}

// If you open two window, the challenge won't match!
$_SESSION['lastForm'] = hash('md5', microtime(true));

?>

<!DOCTYPE html>
<html>
<body>

<form action="/index.php" method="post">
  Encryption: <keygen name="security" keytype="rsa" challenge="<?php echo $_SESSION['lastForm']; ?>"/>
  <input type="submit">
</form>

</body>
</html>