code: public Optional<OpenCryptoFile> get(Path ciphertextPath) {
  		Path normalizedPath = ciphertextPath.toAbsolutePath().normalize();
  		return Optional.ofNullable(openCryptoFiles.get(normalizedPath));
  	}
docs: Gets an OpenCryptoFile (if any is opened) without creating it.
  <p>
  Useful if you don't want to create any FileChannel but want to check whether this file is currently opened (e.g. to get its current {@link OpenCryptoFile#size()}).
  
  @param ciphertextPath Path of the file which might have been opened
  @return The OpenCryptoFile if opened or an empty Optional otherwise.