openssl_spki_verify

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

openssl_spki_verify — Vérifie une clé publique signée, et effectue un challenge

Description

openssl_spki_verify(string $spki): bool

Vérifie une clé publique signée, et effectue un challenge.

Liste de paramètres

spki: Une clé publique signée valide

Valeurs de retour

Cette fonction retourne true en cas de succès ou false si une erreur survient.

Erreurs / Exceptions

Émets une alerte de niveau E_WARNING si un argument invalide est passé au paramètre spkac parameter.

Exemples

Exemple #1 Exemple avec openssl_spki_verify()

Valide une clé publique signée existante et effectue un 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";
}
?>

Exemple #2 Exemple avec openssl_spki_verify() depuis <keygen>

Valide une clé publique signée existante issue d'un élément <keygen>

<?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">

Voir aussi

openssl_spki_new() - Génère une clé publique signée et effectue un challenge
openssl_spki_export_challenge() - Exporte le challenge associé avec la clé publique signée
openssl_spki_export() - Exporte un PEM valide formaté comme une clé publique signée
openssl_get_md_methods() - Récupère la liste des méthodes digest disponibles
openssl_csr_new() - Génère une CSR
openssl_csr_sign() - Signe un CSR avec un autre certificat (ou lui-même) et génère un certificat

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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>

down

neat at neato dot com ¶

4 years ago

The challenge is not how to very a "trick". It is used as a partial non-repudiation method.

The idea was the challenge could be extracted from the base64 encoded ASN.1 PKCS#1 bits provided from the 'keygen' element.

The SPKAC is a form of CSR which if the right about of information such as the commonName, emailAddress, countryName, stateOrProvinceName, localityName et al., a signed x509 could generated and provided to the requestor.

This would then be installed in the browser and if the webserver was configured to accept client x509 certificates, it would be used in lieu of a password for authentication.

A recommendation was to use the 'challenge' as a form of non-repudiation in the event someone else was on your keyboard. If the application required it could prompt you for the challenge and compare it to a hashed version it stored upon the initial SPKAC process.

Hope that helps clear it up.

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