code: public function createSealedResponse(
          int $status,
          string $body,
          SealingPublicKey $key,
          array $headers = [],
          string $version = '1.1'
      ): ResponseInterface {
          return new Response(
              $status,
              new Headers($headers),
              $this->stringToStream(
                  Base64UrlSafe::encode(Simple::seal($body, $key))
              )
          );
      }
docs: Encrypt your HTTP response with the client's public key, so that only
  the client can decrypt the message.
  
  @param int $status
  @param string $body
  @param SealingPublicKey $key
  @param array $headers
  @param string $version
  @return ResponseInterface