# Step Certificates

An online certificate authority and related tools for secure automated certificate management, so you can use TLS everywhere.

This repository is for `step-ca`, a certificate authority that exposes an API for automated certificate management. It also contains a [golang SDK](https://github.com/smallstep/certificates/tree/master/examples#basic-client-usage) for interacting with `step-ca` programatically. However, you'll probably want to use the [`step` command-line tool](https://github.com/smallstep/cli) to operate `step-ca` and get certificates, instead of using this low-level SDK directly.

**Questions? Find us [on gitter](https://gitter.im/smallstep/community).**

[Website](https://smallstep.com) |
[Documentation](#documentation) |
[Installation Guide](#installation-guide) |
[Getting Started](./docs/GETTING_STARTED.md) |
[Contribution Guide](./docs/CONTRIBUTING.md)

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![Animated terminal showing step certificates in practice](https://github.com/smallstep/certificates/raw/master/docs/images/step-ca-2-legged.gif)

## Features

It's super easy to get started and to operate `step-ca` thanks to [streamlined initialization](https://github.com/smallstep/certificates#lets-get-started) and [safe, sane defaults](https://github.com/smallstep/certificates/blob/master/docs/defaults.md). **Get started in 15 minutes.**

### A private certificate authority you run yourself

- Issue client and server certificates to VMs, containers, devices, and people using internal hostnames and emails
- [RFC5280](https://tools.ietf.org/html/rfc5280) and [CA/Browser Forum](https://cabforum.org/baseline-requirements-documents/) compliant certificates that work **for TLS and HTTPS**
- Choose key types (RSA, ECDSA, EdDSA) & lifetimes to suit your needs
- [Short-lived certificates](https://smallstep.com/blog/passive-revocation.html) with **fully automated** enrollment, renewal, and revocation
- Fast, stable, and capable of high availability deployment using [root federation](https://smallstep.com/blog/step-v0.8.3-federation-root-rotation.html) and/or multiple intermediaries
- Operate as an online intermediate for an existing root CA
- [Pluggable database backends](https://github.com/smallstep/certificates/blob/master/docs/database.md) for persistence
- [Helm charts](https://hub.helm.sh/charts/smallstep/step-certificates), [autocert](https://github.com/smallstep/autocert), and [cert-manager integration](https://github.com/smallstep/step-issuer) for kubernetes

### Lots of (automatable) ways to get certificates

- [Single sign-on](https://smallstep.com/blog/easily-curl-services-secured-by-https-tls.html) using Okta, GSuite, Active Directory, or any other OAuth OIDC identity provider
- [Instance identity documents](https://smallstep.com/blog/embarrassingly-easy-certificates-on-aws-azure-gcp/) for VMs on AWS, GCP, and Azure
- [Single-use short-lived tokens](https://smallstep.com/docs/design-doc.html#jwk-provisioner) issued by your CD tool — Puppet, Chef, Ansible, Terraform, etc.
- Use an existing certificate from another CA (e.g., using a device certificate like [Twilio's Trust OnBoard](https://www.twilio.com/wireless/trust-onboard)) *coming soon*

### [Your own private ACME Server](https://smallstep.com/blog/private-acme-server/)
- Issue certificates using ACMEv2 ([RFC8555](https://tools.ietf.org/html/rfc8555)), **the protocol used by Let's Encrypt**
- Great for [using ACME in development & pre-production](https://smallstep.com/blog/private-acme-server/#local-development-pre-production)
- Supports the `http-01`, `tls-alpn-01`, and `dns-01` ACME challenge types
- Works with any compliant ACME client including [certbot](https://smallstep.com/blog/private-acme-server/#certbot-uploads-acme-certbot-png-certbot-example), [acme.sh](https://smallstep.com/blog/private-acme-server/#acme-sh-uploads-acme-acme-sh-png-acme-sh-example), [Caddy](https://smallstep.com/blog/private-acme-server/#caddy-uploads-acme-caddy-png-caddy-example), and [traefik](https://smallstep.com/blog/private-acme-server/#traefik-uploads-acme-traefik-png-traefik-example)
- Get certificates programmatically (e.g., in [Go](https://smallstep.com/blog/private-acme-server/#golang-uploads-acme-golang-png-go-example), [Python](https://smallstep.com/blog/private-acme-server/#python-uploads-acme-python-png-python-example), [Node.js](https://smallstep.com/blog/private-acme-server/#node-js-uploads-acme-node-js-png-node-js-example))

### [SSH Certificates](https://smallstep.com/blog/use-ssh-certificates/)

- Use [certificate authentication for SSH](https://smallstep.com/blog/use-ssh-certificates/): connect SSH to SSO, improve security, and eliminate warnings & errors
- Issue SSH user certificates using OAuth OIDC
- Issue SSH host certificates to cloud VMs using instance identity documents

### Easy certificate management and automation via [`step` CLI](https://github.com/smallstep/cli) [integration](https://smallstep.com/docs/cli/ca/)

- Generate key pairs where they're needed so private keys are never transmitted across the network
- [Authenticate and obtain a certificate](https://smallstep.com/docs/cli/ca/certificate/) using any enrollment mechanism supported by `step-ca`
- Securely [distribute root certificates](https://smallstep.com/docs/cli/ca/root/) and [bootstrap](https://smallstep.com/docs/cli/ca/bootstrap/) PKI relying parties
- [Renew](https://smallstep.com/docs/cli/ca/renew/) and [revoke](https://smallstep.com/docs/cli/ca/revoke/) certificates issued by `step-ca`
- [Install root certificates](https://smallstep.com/docs/cli/certificate/install/) so your CA is trusted by default (issue development certificates **that [work in browsers](https://smallstep.com/blog/step-v0-8-6-valid-HTTPS-certificates-for-dev-pre-prod.html)**)
- [Inspect](https://smallstep.com/docs/cli/certificate/inspect/) and [lint](https://smallstep.com/docs/cli/certificate/lint/) certificates

## Motivation

Managing your own *public key infrastructure* (PKI) can be tedious and error
prone. Good security hygiene is hard. Setting up simple PKI is out of reach for
many small teams, and following best practices like proper certificate
revocation and rolling is challenging even for experts.

Amongst numerous use cases, proper PKI makes it easy to use mTLS (mutual TLS)
to improve security and to make it possible to connect services across the
public internet. Unlike VPNs & SDNs, deploying and scaling mTLS is pretty
easy. You're (hopefully) already using TLS, and your existing tools and
standard libraries will provide most of what you need. If you know how to
operate DNS and reverse proxies, you know how to operate mTLS
infrastructure.

![Connect it all with
mTLS](https://raw.githubusercontent.com/smallstep/certificates/master/docs/images/connect-with-mtls-2.png)

There's just one problem: **you need certificates issued by your own
certificate authority (CA)**. Building and operating a CA, issuing
certificates, and making sure they're renewed before they expire is tricky.
This project provides the infrastructure, automations, and workflows you'll
need.

`step certificates` is part of smallstep's broader security architecture, which
makes it much easier to implement good security practices early, and
incrementally improve them as your system matures.

For more information and [docs](https://smallstep.com/docs) see [the smallstep
website](https://smallstep.com/certificates) and the [blog
post](https://smallstep.com/blog/step-certificates.html) announcing this project.

## Installation Guide

These instructions will install an OS specific version of the `step-ca` binary on
your local machine.

While `step` is not required to run `step-ca`, it will make your life easier so you'll probably want to [install it](https://github.com/smallstep/cli#installation-guide) too.

### Mac OS

Install `step`  and `step-ca` together via [Homebrew](https://brew.sh/):

<pre><code><b>$ brew install step</b>

# Test installation ...
<b>$ step certificate inspect https://smallstep.com</b>
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 326381749415081530968054238478851085504954 (0x3bf265673332db2d0c70e48a163fb7d11ba)
    Signature Algorithm: SHA256-RSA
        Issuer: C=US,O=Let's Encrypt,CN=Let's Encrypt Authority X3
...</code></pre>

> Note: If you have installed `step` previously through the `smallstep/smallstep`
> tap you will need to run the following commands before installing:
> 
> ```
> $ brew untap smallstep/smallstep
> $ brew uninstall step
> ```

### Linux

#### Debian

1. [Optional] Install `step`.

    Download the latest Debian package from
    [`step` releases](https://github.com/smallstep/cli/releases):

    ```
    $ wget https://github.com/smallstep/cli/releases/download/vX.Y.Z/step-cli_X.Y.Z_amd64.deb
    ```

    Install the Debian package:

    ```
    $ sudo dpkg -i step-cli_X.Y.Z_amd64.deb
    ```

2. Install `step-ca`.

    Download the latest Debian package from [releases](https://github.com/smallstep/certificates/releases):

    ```
    $ wget https://github.com/smallstep/certificates/releases/download/vX.Y.Z/step-certificates_X.Y.Z_amd64.deb
    ```

    Install the Debian package:

    ```
    $ sudo dpkg -i step-certificates_X.Y.Z_amd64.deb
    ```

#### Arch Linux

We are using the [Arch User Repository](https://aur.archlinux.org) to distribute
`step` binaries for Arch Linux.

* [Optional] The `step` binary tarball can be found [here](https://aur.archlinux.org/packages/step-cli-bin/).
* The `step-ca` binary tarball can be found [here](https://aur.archlinux.org/packages/step-ca-bin/).

You can use [pacman](https://www.archlinux.org/pacman/) to install the packages.

### Kubernetes

We publish [helm charts](https://hub.helm.sh/charts/smallstep/step-certificates) for easy installation on kubernetes:

```
helm install step-certificates
```

> <a href="https://github.com/smallstep/autocert"><img width="25%" src="https://raw.githubusercontent.com/smallstep/autocert/master/autocert-logo.png"></a>
>
> If you're using Kubernetes, make sure you [check out
> autocert](https://github.com/smallstep/autocert): a kubernetes add-on that builds on `step
> certificates` to automatically inject TLS/HTTPS certificates into your containers.

### Test

<pre><code><b>$ step version</b>
Smallstep CLI/0.10.0 (darwin/amd64)
Release Date: 2019-04-30 19:01 UTC

<b>$ step-ca version</b>
Smallstep CA/0.10.0 (darwin/amd64)
Release Date: 2019-04-30 19:02 UTC</code></pre>

## Quickstart

In the following guide we'll run a simple `hello` server that requires clients
to connect over an authorized and encrypted channel using HTTPS. `step-ca`
will issue certificates to our server, allowing it to authenticate and encrypt
communication. Let's get started!

### Prerequisites

* [`step`](#installation-guide)
* [golang](https://golang.org/doc/install)

### Let's get started!

#### 1. Run `step ca init` to create your CA's keys & certificates and configure `step-ca`:

<pre><code><b>$ step ca init</b>
✔ What would you like to name your new PKI? (e.g. Smallstep): <b>Example Inc.</b>
✔ What DNS names or IP addresses would you like to add to your new CA? (e.g. ca.smallstep.com[,1.1.1.1,etc.]): <b>localhost</b>
✔ What address will your new CA listen at? (e.g. :443): <b>127.0.0.1:8080</b>
✔ What would you like to name the first provisioner for your new CA? (e.g. you@smallstep.com): <b>bob@example.com</b>
✔ What do you want your password to be? [leave empty and we'll generate one]: <b>abc123</b>

Generating root certificate...
all done!

Generating intermediate certificate...
all done!

✔ Root certificate: /Users/bob/src/github.com/smallstep/step/.step/certs/root_ca.crt
✔ Root private key: /Users/bob/src/github.com/smallstep/step/.step/secrets/root_ca_key
✔ Root fingerprint: 702a094e239c9eec6f0dcd0a5f65e595bf7ed6614012825c5fe3d1ae1b2fd6ee
✔ Intermediate certificate: /Users/bob/src/github.com/smallstep/step/.step/certs/intermediate_ca.crt
✔ Intermediate private key: /Users/bob/src/github.com/smallstep/step/.step/secrets/intermediate_ca_key
✔ Default configuration: /Users/bob/src/github.com/smallstep/step/.step/config/defaults.json
✔ Certificate Authority configuration: /Users/bob/src/github.com/smallstep/step/.step/config/ca.json

Your PKI is ready to go. To generate certificates for individual services see 'step help ca'.</code></pre>

This command will:

- Generate [password protected](https://github.com/smallstep/certificates/blob/master/docs/GETTING_STARTED.md#passwords)  private keys for your CA to sign certificates
- Generate a root and [intermediate signing certificate](https://security.stackexchange.com/questions/128779/why-is-it-more-secure-to-use-intermediate-ca-certificates) for your CA
- Create a JSON configuration file for `step-ca` (see [getting started](./docs/GETTING_STARTED.md) for details)

You can find these artifacts in `$STEPPATH` (or `~/.step` by default).

#### 2. Start `step-ca`:

You'll be prompted for your password from the previous step, to decrypt the CA's private signing key:

<pre><code><b>$ step-ca $(step path)/config/ca.json</b>
Please enter the password to decrypt /Users/bob/src/github.com/smallstep/step/.step/secrets/intermediate_ca_key: <b>abc123</b>
2019/02/18 13:28:58 Serving HTTPS on 127.0.0.1:8080 ...</code></pre>

#### 3. Copy our `hello world` golang server.

```
$ cat > srv.go <<EOF
package main

import (
    "net/http"
    "log"
)

func HiHandler(w http.ResponseWriter, req *http.Request) {
    w.Header().Set("Content-Type", "text/plain")
    w.Write([]byte("Hello, world!\n"))
}

func main() {
    http.HandleFunc("/hi", HiHandler)
    err := http.ListenAndServeTLS(":8443", "srv.crt", "srv.key", nil)
    if err != nil {
        log.Fatal(err)
    }
}
EOF
```

#### 4. Get an identity for your server from the Step CA.

<pre><code><b>$ step ca certificate localhost srv.crt srv.key</b>
✔ Key ID: rQxROEr7Kx9TNjSQBTETtsu3GKmuW9zm02dMXZ8GUEk (bob@example.com)
✔ Please enter the password to decrypt the provisioner key: abc123
✔ CA: https://localhost:8080/1.0/sign
✔ Certificate: srv.crt
✔ Private Key: srv.key

<b>$ step certificate inspect --bundle srv.crt</b>
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 140439335711218707689123407681832384336 (0x69a7a1d7f6f22f68059d2d9088307750)
    Signature Algorithm: ECDSA-SHA256
        Issuer: CN=Example Inc. Intermediate CA
        Validity
            Not Before: Feb 18 21:32:35 2019 UTC
            Not After : Feb 19 21:32:35 2019 UTC
        Subject: CN=localhost
...
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 207035091234452090159026162349261226844 (0x9bc18217bd560cf07db23178ed90835c)
    Signature Algorithm: ECDSA-SHA256
        Issuer: CN=Example Inc. Root CA
        Validity
            Not Before: Feb 18 21:27:21 2019 UTC
            Not After : Feb 15 21:27:21 2029 UTC
        Subject: CN=Example Inc. Intermediate CA
...</code></pre>

Note that `step` and `step-ca` handle details like [certificate bundling](https://smallstep.com/blog/everything-pki.html#intermediates-chains-and-bundling) for you.

#### 5. Run the simple server.

<pre><code><b>$ go run srv.go &</b></code></pre>

#### 6. Get the root certificate from the Step CA.

In a new Terminal window:

<pre><code><b>$ step ca root root.crt</b>
The root certificate has been saved in root.crt.</code></pre>

#### 7. Make an authenticated, encrypted curl request to your server using HTTP over TLS.

<pre><code><b>$ curl --cacert root.crt https://localhost:8443/hi</b>
Hello, world!</code></pre>

*All Done!*

Check out the [Getting Started](./docs/GETTING_STARTED.md) guide for more examples
and best practices on running Step CA in production.

## Documentation

Documentation can be found in a handful of different places:

1. The [docs](./docs/README.md) sub-repo has an index of documentation and tutorials.

2. On the command line with `step help ca xxx` where `xxx` is the subcommand
you are interested in. Ex: `step help ca provisioner list`.

3. On the web at https://smallstep.com/docs/certificates.

4. On your browser by running `step help --http=:8080 ca` from the command line
and visiting http://localhost:8080.


## The Future

We plan to build more tools that facilitate the use and management of zero trust
networks.

* Tell us what you like and don't like about managing your PKI - we're eager to
help solve problems in this space.
* Tell us what features you'd like to see - open issues or hit us on
[Twitter](https://twitter.com/smallsteplabs).

## Further Reading

Check out the [Getting Started](https://smallstep.com/docs/getting-started/) guide for more examples
and best practices on running Step CA in production.