os.Exit(2)
			}
			return &pem.Block{Type: "EC PRIVATE KEY", Bytes: b}
		default:
			return nil
		}
	}

	var priv interface{}
	var err error
	priv, err = rsa.GenerateKey(crand.Reader, rsaBits)
	if err != nil {
		return nil, nil, fmt.Errorf("failed to generate private key: %w", err)
	}

	notBefore := time.Now()
	notAfter := notBefore.Add(validFor)