Swift_Signers_DKIMSigner::getEncryptedHash PHP Method

    private function getEncryptedHash()
    {
        $signature = '';
        switch ($this->hashAlgorithm) {
            case 'rsa-sha1':
                $algorithm = OPENSSL_ALGO_SHA1;
                break;
            case 'rsa-sha256':
                $algorithm = OPENSSL_ALGO_SHA256;
                break;
        }
        $pkeyId = openssl_get_privatekey($this->privateKey);
        if (!$pkeyId) {
            throw new Swift_SwiftException('Unable to load DKIM Private Key [' . openssl_error_string() . ']');
        }
        if (openssl_sign($this->headerCanonData, $signature, $pkeyId, $algorithm)) {
            return $signature;
        }
        throw new Swift_SwiftException('Unable to sign DKIM Hash [' . openssl_error_string() . ']');
    }