Secrets Encryption Config

K3s supports enabling secrets encryption at rest. When first starting the server, passing the flag --secrets-encryption will do the following automatically:

Generate an AES-CBC key
Generate an encryption config file with the generated key
Pass the config to the KubeAPI as encryption-provider-config

Secrets-encryption cannot be enabled on an existing server without restarting it.
Use curl -sfL https://get.k3s.io | sh -s - server --secrets-encryption if installing from script, or other methods described in Configuration Options.

Choosing Encryption Provider

Version Gate

Available as of the April 2025 releases: v1.30.12+k3s1, v1.31.8+k3s1, v1.32.4+k3s1, v1.33.0+k3s1.

Using the --secrets-encryption-provider flag, you can choose from the following K3s-supported encryption providers:

aescbc: AES-CBC with PKCS#7 padding. This is the default provider.
secretbox: XSalsa20 and Poly1305

Generated encryption config file

When you start the server with --secrets-encryption, K3s will generate an encryption config file at /var/lib/rancher/k3s/server/cred/encryption-config.json.

Below is an example of the generated encryption config file with the default aescbc provider:

{
  "kind": "EncryptionConfiguration",
  "apiVersion": "apiserver.config.k8s.io/v1",
  "resources": [
    {
      "resources": [
        "secrets"
      ],
      "providers": [
        {
          "aescbc": {
            "keys": [
              {
                "name": "aescbckey",
                "secret": "xxxxxxxxxxxxxxxxxxx"
              }
            ]
          }
        },
        {
          "identity": {}
        }
      ]
    }
  ]
}

Secrets Encryption Tool

K3s contains a utility tool secrets-encrypt, which enables automatic control over the following:

Disabling/Enabling secrets encryption
Adding new encryption keys
Rotating and deleting encryption keys
Reencrypting secrets

For more information, see the k3s secrets-encrypt command documentation.