Add documentation for the signing feature

Signed-off-by: Kim Christensen <kimworking@gmail.com>

docs/content/docs/configuration/configuration.md

@@ -111,6 +111,10 @@ default-secrets: "mysecrets"
 # the configuration in the secrets section.
 default-secrets-plugin: "kubernetes.secret"
 
+# Use the signer configuration name mysigner.
+# If not specified, bundles and invocation images cannot be signed.
+default-signer: "mysigner"
+
 # Defines storage accounts
 storage:
   # The storage account name
@@ -145,6 +149,23 @@ secrets:
       # The subscription where the vault is defined
       subscription-id: "${env.AZURE_SUBSCRIPTION_ID}"
 
+# Define signers
+signer:
+  # The signer name
+  - name: "mysigner"
+
+    # The plugin used to sign bundles
+    plugin: "cosign"
+
+    # Additional configuration for the signer
+    # These values vary depending on the plugin used
+    config:
+      # Path to the public key
+      publickey: /home/porter/cosign.pub
+
+      # Path to the public key
+      privatekey: /home/porter/cosign.key
+
 # Log command output to a file in PORTER_HOME/logs/
 logs:
   # Log command output to a file

docs/content/docs/operations/signing-bundles.md

@@ -4,4 +4,89 @@ description: Signing of Porter bundles
 weight: 7
 ---
 
-TODO
+Porter has built-in support for signing bundles and the associated invocation image using [Cosign] or [Notation].
+Learn how to configure Porter to sign bundles.
+
+- [Cosign](#cosign)
+- [Notation](#notation)
+
+## Cofiguration
+
+### Cosign
+
+#### Prerequisites
+
+1. Cosign is installed and is available on the on the `PATH`.
+2. A key-pair for signing is available.
+
+Instructions on for the install Cosign can be found on the [Cosign Installation page](https://docs.sigstore.dev/system_config/installation/), and instructions on how to generate a key-pair can be found in the [Cosign Quickstart Guide](https://docs.sigstore.dev/signing/quickstart/#signing-with-a-generated-key).
+
+🚧 Currently Porter does not support [Keyless Signing](https://docs.sigstore.dev/signing/overview/).
+
+#### Configuration
+
+Porter have to be configure to use [Cosign] to sign bundles and invocation images. All configuration is done through the [Porter config file](/docs/configuration/configuration/). To configure [Cosign] add the following to the configuration file.
+
+```yaml
+# ~/.porter/config.yaml
+
+default-signer: "mysigner"
+
+signer:
+  - name: "mysigner"
+    plugin: "cosign"
+    config:
+      publickey: <PATH_TO_PUBLIC_KEY>
+      privatekey: <PATH_TO_PRIVATE_KEY>
+
+      # Set the mode for fetching references from the registry. allowed: legacy, oci-1-1.
+      # If set to oci-1-1, experimental must be set the true.
+      # registrymode: legacy
+
+      # Enable Cosign experimental features.
+      # Required if regsitrymode is set to oci-1-1.
+      # experimental: false
+
+      # Allow signing of bundles in registries with expired or self-signed certificates.
+      # insecureregistry: false
+```
+
+### Notation
+
+#### Prerequisites
+
+1. Notation is installed and is available on the on the `PATH`.
+2. A signing key and certificate have been configured.
+3. A trust policy for verification have been configured.
+
+Instructions on for the install Notation can be found on the [Notation Installation page](https://notaryproject.dev/docs/user-guides/installation/cli/), and instructions on how to configure a signing key, certificate and trust policy can be found in the [Notation Quickstart Guide](https://notaryproject.dev/docs/quickstart-guides/quickstart-sign-image-artifact/).
+
+#### Configuration
+
+Porter have to be configure to use [Notation] to sign bundles and invocation images. All configuration is done through the [Porter config file](/docs/configuration/configuration/). To configure [Notation] add the following to the configuration file.
+
+```yaml
+# ~/.porter/config.yaml
+
+default-signer: "mysigner"
+
+signer:
+  - name: "mysigner"
+    plugin: "notation"
+    config:
+      key: <NAME_OF_KEY>
+
+      # Allow signing of bundles HTTP registries
+      # insecureregistry: false
+```
+
+## Sign bundle
+
+To sign run [porter publish](/cli/porter_publish/) with the `--sign-bundle` flag.
+
+## Verify bundle
+
+A bundle can be verified before installation by adding the `--verify-bundle` flag to [porter install](/cli/porter_publish/).
+
+[Cosign]: https://docs.sigstore.dev/signing/quickstart/
+[Notation]: https://notaryproject.dev/docs/quickstart-guides/quickstart-sign-image-artifact/