keyUsage = x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment
	}

	extKeyUsages := []x509.ExtKeyUsage{}
	if options.IsServer {
		extKeyUsages = append(extKeyUsages, x509.ExtKeyUsageServerAuth)
	}
	if options.IsClient {
		extKeyUsages = append(extKeyUsages, x509.ExtKeyUsageClientAuth)
	}

	notBefore := time.Now()
	if !options.NotBefore.IsZero() {

			return nil, nil, errors.New("x509: invalid extended key usages")
		}
		if extKeyUsage, ok := extKeyUsageFromOID(eku); ok {
			extKeyUsages = append(extKeyUsages, extKeyUsage)
		} else {
			unknownUsages = append(unknownUsages, eku)
		}
	}
	return extKeyUsages, unknownUsages, nil
}

func parseCertificatePoliciesExtension(der cryptobyte.String) ([]OID, error) {
	var oids []OID