We generate certificates that are intended to be used for server authentication in a couple of places:

- `bin/elasticsearch-certutil http` command  ( See `CertGenUtils.generateSignedCertificate` in `HttpCertificateCommand` )
- TLS auto-configuraion for node startup ( see [`AutoConfigureNode`](https://github.com/elastic/elasticsearch/blob/814f7f9f52cb8c05db6465b9bfc818ea5d76c575/x-pack/plugin/security/cli/src/main/java/org/elasticsearch/xpack/security/cli/AutoConfigureNode.java#L454) )

In these cases we know that the certificate is meant to be used for server authentication, so we can set Extended Key Usage extension to `1.3.6.1.5.5.7.3.1`
x-pack/plugin/security/cli/src/main/java/org/elasticsearch/xpack/security/cli/HttpCertificateCommand.java
return size;
            } catch (NumberFormatException e) {
                terminal.println("The key size must be a positive integer");
                return null;
            }
        });
    }
    private char[] readPassword(Terminal terminal, String prompt, boolean confirm) {
        while (true) {
            final char[] password = terminal.readSecret(prompt + " [<ENTER> for none]");
            if (password.length == 0) {
                return password;
            }
            if (CertificateTool.isAscii(password)) {
                if (confirm) {
                    final char[] again = terminal.readSecret("Repeat password to confirm: ");
                    if (Arrays.equals(password, again) == false) {
                        terminal.println("Passwords do not match");
                        continue;
                    }
                }
                if (CertificateTool.checkAndConfirmPasswordLengthForOpenSSLCompatibility(password, terminal, confirm) == false) {
                    continue;
                }
                return password;
            } else {
                terminal.println(Terminal.Verbosity.SILENT, "Passwords must be plain ASCII");
            }
        }
    }