code: func (g *GPG) Decrypt(ctx context.Context, ciphertext []byte) ([]byte, error) {
  	md, err := openpgp.ReadMessage(bytes.NewReader(ciphertext), g, g.mkPromptFunc(), nil)
  	if err != nil {
  		return nil, err
  	}
  	buf := &bytes.Buffer{}
  	if _, err := io.Copy(buf, md.UnverifiedBody); err != nil {
  		return nil, err
  	}
  	return buf.Bytes(), nil
  }
docs: // Decrypt decryptes the ciphertext
  // see https://gist.github.com/stuart-warren/93750a142d3de4e8fdd2