OpenPGP signing

The matchbox OpenPGP signature endpoints serve detached binary and ASCII armored signatures of rendered configs, if enabled. Each config endpoint has corresponding signature endpoints, typically suffixed with .sig or .asc.

To enable OpenPGP signing, provide the path to a secret keyring containing a single signing key with -key-ring-path or by setting MATCHBOX_KEY_RING_PATH. If a passphrase is required, set it via the MATCHBOX_PASSPHRASE environment variable.

Here are example signature endpoints without their query parameters.

Endpoint	Signature Endpoint	ASCII Signature Endpoint
iPXE	http://matchbox.foo/ipxe.sig	http://matchbox.foo/ipxe.asc
GRUB2	http://bootcf.foo/grub.sig	http://matchbox.foo/grub.asc
Ignition	http://matchbox.foo/ignition.sig	http://matchbox.foo/ignition.asc
Cloud-Config	http://matchbox.foo/cloud.sig	http://matchbox.foo/cloud.asc
Metadata	http://matchbox.foo/metadata.sig	http://matchbox.foo/metadata.asc

In production, mount your signing keyring and source the passphrase from a Kubernetes secret. Use a signing subkey exported to a keyring by itself, which can be revoked by a primary key, if needed.

To try it locally, you may use the test fixture keyring. Warning: The test fixture keyring is for examples only.

Verify

Verify a signature response and config response from the command line using the public key. Notice that most configs have a trailing newline.

Warning: The test fixture keyring is for examples only.

$ gpg --homedir sign/fixtures --verify sig_file response_file
gpg: Signature made Mon 08 Feb 2016 11:37:03 PM PST using RSA key ID 9896356A
gpg: sign/fixtures/trustdb.gpg: trustdb created
gpg: Good signature from "Fake Bare Metal Key (Do not use) <do-not-use@example.com>"
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: BE2F 12BC 3642 2594 570A  CCBB 8DC4 2020 9896 356A

Signing key generation

Create a signing key or subkey according to your requirements and security policies. Here are some basic guides.

gpg

$ mkdir -m 700 path/in/vault
$ gpg --homedir path/in/vault --expert --gen-key
...

gpg2

$ mkdir -m 700 path/in/vault
$ gpg2 --homedir path/in/vault --expert --gen-key
...
$ gpg2 --homedir path/in/vault --export-secret-key KEYID > path/in/vault/secring.gpg