Jose\Factory\JWKFactory::createECKey PHP Method

    public static function createECKey(array $values)
    {
        Assertion::keyExists($values, 'crv', 'The curve is not set.');
        $curve = $values['crv'];
        if (function_exists('openssl_get_curve_names')) {
            $args = ['curve_name' => self::getOpensslName($curve), 'private_key_type' => OPENSSL_KEYTYPE_EC];
            $key = openssl_pkey_new($args);
            $res = openssl_pkey_export($key, $out);
            Assertion::true($res, 'Unable to create the key');
            $rsa = new ECKey($out);
            $values = array_merge($values, $rsa->toArray());
            return new JWK($values);
        } else {
            $curve_name = self::getNistName($curve);
            $generator = CurveFactory::getGeneratorByName($curve_name);
            $private_key = $generator->createPrivateKey();
            $values = array_merge($values, ['kty' => 'EC', 'crv' => $curve, 'x' => self::encodeValue($private_key->getPublicKey()->getPoint()->getX()), 'y' => self::encodeValue($private_key->getPublicKey()->getPoint()->getY()), 'd' => self::encodeValue($private_key->getSecret())]);
        }
        return new JWK($values);
    }

 /**
  * {@inheritdoc}
  */
 public function getAgreementKey($encryption_key_length, $algorithm, JWKInterface $recipient_key, array $complete_header = [], array &$additional_header_values = [])
 {
     if ($recipient_key->has('d')) {
         $this->checkKey($recipient_key, true);
         $private_key = $recipient_key;
         $public_key = $this->getPublicKey($complete_header);
     } else {
         $this->checkKey($recipient_key, false);
         $public_key = $recipient_key;
         switch ($public_key->get('crv')) {
             case 'P-256':
             case 'P-384':
             case 'P-521':
                 $private_key = JWKFactory::createECKey(['crv' => $public_key->get('crv')]);
                 break;
             case 'X25519':
                 $private_key = JWKFactory::createOKPKey(['crv' => 'X25519']);
                 break;
             default:
                 throw new \InvalidArgumentException(sprintf('The curve "%s" is not supported', $public_key->get('crv')));
         }
         $epk = $private_key->toPublic()->getAll();
         $additional_header_values = array_merge($additional_header_values, ['epk' => $epk]);
     }
     Assertion::eq($private_key->get('crv'), $public_key->get('crv'), 'Curves are different');
     $agreed_key = $this->calculateAgreementKey($private_key, $public_key);
     $apu = array_key_exists('apu', $complete_header) ? $complete_header['apu'] : '';
     $apv = array_key_exists('apv', $complete_header) ? $complete_header['apv'] : '';
     return ConcatKDF::generate($agreed_key, $algorithm, $encryption_key_length, $apu, $apv);
 }