val root =
      HeldCertificate.Builder()
        .certificateAuthority(1)
        .build()
    val intermediate =
      HeldCertificate.Builder()
        .certificateAuthority(0)
        .signedBy(root)
        .build()
    val certificate =
      HeldCertificate.Builder()
        .signedBy(intermediate)
        .build()
    val handshakeCertificates =
      HandshakeCertificates.Builder()

     *
     * The chain should include all intermediate certificates but does not need the root certificate
     * that we expect to be known by the remote peer. The peer already has that certificate so
     * transmitting it is unnecessary.
     */
    fun heldCertificate(
      heldCertificate: HeldCertificate,
      vararg intermediates: X509Certificate,
    ) = apply {

# Istio Agent

This document describes the internal architecture of Istio agent.

## High Level overview

![High Level overview](docs/overview.svg)

At a high level, the Istio agent acts as an intermediate proxy between Istiod and Envoy. This is done
at two levels. For distributing workload certificates, Envoy will send [SDS](https://www.envoyproxy.io/docs/envoy/latest/configuration/security/secret)

representative of real-world HTTPS deployment. To get closer to that we can use `HeldCertificate`
to generate a trusted root certificate, an intermediate certificate, and a server certificate.
We use `certificateAuthority(int)` to create certificates that can sign other certificates. The
int specifies how many intermediate certificates are allowed beneath it in the chain.

```java
HeldCertificate rootCertificate = new HeldCertificate.Builder()

### Choosing between application and network interceptors

Each interceptor chain has relative merits.

**Application interceptors**

 * Don't need to worry about intermediate responses like redirects and retries.
 * Are always invoked once, even if the HTTP response is served from the cache.
 * Observe the application's original intent. Unconcerned with OkHttp-injected headers like `If-None-Match`.

  }

  /**
   * Returns true if [toVerify] was signed by [signingCert]'s public key.
   *
   * @param minIntermediates the minimum number of intermediate certificates in [signingCert]. This
   *     is -1 if signing cert is a lone self-signed certificate.
   */
  private fun verifySignature(
    toVerify: X509Certificate,
    signingCert: X509Certificate,

internal data class BasicConstraints(
  /** True if this certificate can be used as a Certificate Authority (CA). */
  val ca: Boolean,
  /** The maximum number of intermediate CAs between this and leaf certificates. */
  val maxIntermediateCas: Long?,
)

/** A private key. Note that this class doesn't support attributes or an embedded public key. */
internal data class PrivateKeyInfo(

With rewrites, redirects, follow-ups and retries, your simple request may yield many requests and responses. OkHttp uses `Call` to model the task of satisfying your request through however many intermediate requests and responses are necessary. Typically this isn’t many! But it’s comforting to know that your code will continue to work if your URLs are redirected or if you failover to an alternate IP address.

  @Throws(IOException::class)
  fun finishRequest()

  /**
   * Parses bytes of a response header from an HTTP transport.
   *
   * @param expectContinue true to return null if this is an intermediate response with a "100"
   * response code. Otherwise this method never returns null.
   */
  @Throws(IOException::class)
  fun readResponseHeaders(expectContinue: Boolean): Response.Builder?

* Inside the `certs` directory, the private key must by named `private.key` and the public key must be named `public.crt`.
* A certificate signed by a CA contains information about the issued identity (e.g. name, expiry, public key) and any intermediate certificates. The root CA is not included.

## 3. Generate and use Self-signed Keys and Certificates with MinIO

This section describes how to generate a self-signed certificate using various tools: