/** * Sign a message, using your secret key * * @param string|resource $sealed * @param EncryptionPublicKey $publicKey * @return string */ public function signAsymmetric($message, SignatureSecretKey $secretKey, array $options = []) : string { $signature = ''; $signed = \openssl_sign($message, $signature, $secretKey->getPEM(), 'sha384WithRSAEncryption'); if ($signed) { return binhex($signature); } }