![SDS decision flow](docs/sds-flow.svg)

### Default CA Flow through istio-agent

![CA Flow](docs/ca.svg)

A single SDS request from Envoy goes through a few different layers in istio-agent.

      val trustedCert = trustRootIndex.findByIssuerAndSignature(toVerify)
      if (trustedCert != null) {
        if (result.size > 1 || toVerify != trustedCert) {
          result.add(trustedCert)
        }
        if (verifySignature(trustedCert, trustedCert, result.size - 2)) {
          return result // The self-signed cert is a root CA. We're done.
        }

 * certificate is signed by the certificate that follows, and the last certificate is a trusted CA
 * certificate.
 *
 * Use of the chain cleaner is necessary to omit unexpected certificates that aren't relevant to
 * the TLS handshake and to extract the trusted CA certificate for the benefit of certificate
 * pinning.
 */
abstract class CertificateChainCleaner {

    key_file:   "./testdata/contrib/certs/nats_server_key.pem"
    ca_file:   "./testdata/contrib/certs/root_ca_cert.pem"
    verify_and_map: true
}
authorization {
    ADMIN = {
        publish = ">"
        subscribe = ">"
    }
    users = [
        {user: "CN=localhost,OU=Client,O=MinIO,C=CA", permissions: $ADMIN}
    ]

fake-CA-cert...

fake-CA-cert...

* 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

FROM golang:1.21-alpine as build

ARG TARGETARCH
ARG RELEASE

ENV GOPATH /go
ENV CGO_ENABLED 0

# Install curl and minisign
RUN apk add -U --no-cache ca-certificates && \
    apk add -U --no-cache curl && \
    go install aead.dev/minisign/cmd/minisign@v0.2.1

# Download minio binary and signature file
RUN curl -s -q https://dl.min.io/server/minio/hotfixes/linux-${TARGETARCH}/archive/minio.${RELEASE} -o /go/bin/minio && \

# hadolint ignore=DL3005,DL3008
RUN apt-get update && \
  apt-get install --no-install-recommends -y \
  ca-certificates \
  curl \
  iptables \
  iproute2 \
  iputils-ping \
  knot-dnsutils \
  netcat-openbsd \
  tcpdump \
  conntrack \
  bsdmainutils \
  net-tools \
  lsof \
  sudo \
  && update-ca-certificates \
  && apt-get upgrade -y \
  && apt-get clean \

FROM golang:1.21-alpine as build

ARG TARGETARCH
ARG RELEASE

ENV GOPATH /go
ENV CGO_ENABLED 0

# Install curl and minisign
RUN apk add -U --no-cache ca-certificates && \
    apk add -U --no-cache curl && \
    go install aead.dev/minisign/cmd/minisign@v0.2.1

# Download minio binary and signature file
RUN curl -s -q https://dl.min.io/server/minio/release/linux-${TARGETARCH}/archive/minio.${RELEASE} -o /go/bin/minio && \