Filesystem Keystore

This guide shows how to setup a KES server that uses the filesystem as persistent key store.

                         ╔══════════════════════════════════════════╗
┌────────────┐           ║  ┌────────────┐          ┌────────────┐  ║
│ KES Client ├───────────╫──┤ KES Server ├──────────┤ Filesystem │  ║
└────────────┘           ║  └────────────┘          └────────────┘  ║
                         ╚══════════════════════════════════════════╝

A plain filesystem does not provide any protection for the stored keys. It should only be used for testing purposes.

---

KES Server Setup

1. Generate private key & certificate for KES server

First, we need to generate a TLS private key and certificate for our KES server. A KES server can only be run with TLS - since secure-by-default. Here we use self-signed certificates for simplicity.

The following command generates a new TLS private key (private.key) and a self-signed X.509 certificate (public.crt) issued for the IP 127.0.0.1 and DNS name localhost:

$ kes identity new --ip "127.0.0.1" localhost

  Private key:  private.key
  Certificate:  public.crt
  Identity:     2e897f99a779cf5dd147e58de0fe55a494f546f4dcae8bc9e5426d2b5cd35680

If you already have a TLS private key & certificate - e.g. from a WebPKI or internal CA - you can use them instead. Remember to adjust the tls config section later on.

2. Generate client access credentials

The client application needs some credentials to access the KES server. The following command generates a new TLS private/public key pair:

$ kes identity new --key=client.key --cert=client.crt MyApp

  Private key:  client.key
  Certificate:  client.crt
  Identity:     02ef5321ca409dbc7b10e7e8ee44d1c3b91e4bf6e2198befdebee6312745267b

The identity 02ef5321ca409dbc7b10e7e8ee44d1c3b91e4bf6e2198befdebee6312745267b is an unique fingerprint of the public key in client.crt and you can re-compute it anytime:

$ kes identity of client.crt

  Identity:  02ef5321ca409dbc7b10e7e8ee44d1c3b91e4bf6e2198befdebee6312745267b

3. Configure KES server

Next, we can create the KES server configuration file: config.yml. Please, make sure that the identity in the policy section matches your client.crt identity.

address: 0.0.0.0:7373 # Listen on all network interfaces on port 7373

admin:
  identity: disabled  # We disable the admin identity since we don't need it in this guide 
   
tls:
  key: private.key    # The KES server TLS private key
  cert: public.crt    # The KES server TLS certificate
   
policy:
  my-app: 
    allow:
    - /v1/key/create/my-key*
    - /v1/key/generate/my-key*
    - /v1/key/decrypt/my-key*
    identities:
    - 02ef5321ca409dbc7b10e7e8ee44d1c3b91e4bf6e2198befdebee6312745267b # Use the identity of your client.crt
   
keystore:
  fs:
    path: ./keys # Choose a directory for the secret keys

4. Start KES server

Now, we can start a KES server instance:

$ kes server --config config.yml --auth off

KES CLI Access

1. Set KES_SERVER endpoint

The KES CLI needs to know to which server it should talk to:

$ export KES_SERVER=https://127.0.0.1:7373

2. Use client credentials

Further, the KES CLI needs some access credentials to talk to a KES server:

$ export KES_CLIENT_CERT=client.crt

$ export KES_CLIENT_KEY=client.key

3. Perform operations

Now, we can perform any API operation that is allowed based on the policy we assigned above. For example we can create a key:

$ kes key create my-key-1

Then, we can use that key to generate a new data encryption key:

$ kes key dek my-key-1
{
  plaintext : UGgcVBgyQYwxKzve7UJNV5x8aTiPJFoR+s828reNjh0=
  ciphertext: eyJhZWFkIjoiQUVTLTI1Ni1HQ00tSE1BQy1TSEEtMjU2IiwiaWQiOiIxMTc1ZjJjNDMyMjNjNjNmNjY1MDk5ZDExNmU3Yzc4NCIsIml2IjoiVHBtbHpWTDh5a2t4VVREV1RSTU5Tdz09Iiwibm9uY2UiOiJkeGl0R3A3bFB6S21rTE5HIiwiYnl0ZXMiOiJaaWdobEZrTUFuVVBWSG0wZDhSYUNBY3pnRWRsQzJqWFhCK1YxaWl2MXdnYjhBRytuTWx0Y3BGK0RtV1VoNkZaIn0=
}

References

• Server API Doc
• Go SDK Doc