(PHP 5 >= 5.6.0, PHP 7, PHP 8)
openssl_spki_export_challenge — Exports the challenge associated with a signed public key and challenge
$spki): string|falseExports challenge from encoded signed public key and challenge
spkiExpects a valid signed public key and challenge
Returns the associated challenge string or false on failure.
Emits an E_WARNING level error if an invalid argument
is passed via the spki parameter.
Example #1 openssl_spki_export_challenge() example
Extracts the associated challenge string or NULL on failure.
<?php
$pkey = openssl_pkey_new('secret password');
$spkac = openssl_spki_new($pkey, 'challenge string');
$challenge = openssl_spki_export_challenge(preg_replace('/SPKAC=/', '', $spkac));
?>
Example #2 openssl_spki_export_challenge() example from <keygen>
Extracts the associated challenge string issued from the <keygen> element
<?php
$challenge = openssl_spki_export_challenge(preg_replace('/SPKAC=/', '', $_POST['spkac']));
?>
<keygen name="spkac" challenge="challenge string" keytype="RSA">