KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth, x509.ExtKeyUsageClientAuth},
		BasicConstraintsValid: true,
	}
	if mode&^boringCertFIPSOK == boringCertLeaf {
		tmpl.DNSNames = []string{"example.com"}
	} else {
		tmpl.IsCA = true
		tmpl.KeyUsage |= x509.KeyUsageCertSign
	}

	// encryption key could only be used for Diffie-Hellman key agreement.

	if certType == intermediateCertificate && (!c.BasicConstraintsValid || !c.IsCA) {
		return CertificateInvalidError{c, NotAuthorizedToSign, ""}
	}

	if c.BasicConstraintsValid && c.MaxPathLen >= 0 {
		numIntermediates := len(currentChain) - 1
		if numIntermediates > c.MaxPathLen {

				if err != nil {
					return err
				}
			case 19:
				out.IsCA, out.MaxPathLen, err = parseBasicConstraintsExtension(e.Value)
				if err != nil {
					return err
				}
				out.BasicConstraintsValid = true
				out.MaxPathLenZero = out.MaxPathLen == 0
			case 17:
				out.DNSNames, out.EmailAddresses, out.IPAddresses, out.URIs, err = parseSANExtension(e.Value)
				if err != nil {
					return err
				}