code: func (w *Writer) Encrypt(name string, password string) (io.Writer, error) {
  	fh := &FileHeader{
  		Name:   name,
  		Method: Deflate,
  	}
  	fh.SetPassword(password)
  	return w.CreateHeader(fh)
  }
docs: // Encrypt adds a file to the zip file using the provided name.
  // It returns a Writer to which the file contents should be written. File
  // contents will be encrypted with AES-256 using the given password. The
  // file's contents must be written to the io.Writer before the next call
  // to Create, CreateHeader, or Close.