gcloud container binauthz attestors public-keys - create and manage public keys associated with Attestation Authorities
gcloud container binauthz attestors public-keys COMMAND [GCLOUD_WIDE_FLAG ...]
GPG is a common tool that implements the PGP standard.
For general gpg usage examples, see gcloud alpha container binauthz help.
For more detailed and complete documentation, see the GPG manual: https://gnupg.org/documentation/manuals.html
To get the fingerprint of the public key:
$ gpg \ --with-colons \ --with-fingerprint \ --force-v4-certs \ --list-keys \ "${ATTESTING_USER}" | grep fpr | cut --delimiter=':' --fields 10
To export a public key:
$ gpg \ --armor \ --export "${FINGERPRINT}" \ --output public_key1.pgp
To add your new key to the attestor:
$ gcloud container binauthz attestors public-keys add \ --attestor my_attestor \ --pgp-public-key-file=public_key1.pgp
To add a subkey to your PGP key:
$ gpg \ --quick-add-key ${FINGERPRINT} \ default \ sign
To revoke a subkey from your PGP key:
$ gpg \ --edit-key ${FINGERPRINT}
sec rsa2048/8C124F0F782DA097 created: 2018-01-01 expires: never usage: SCEA trust: ultimate validity: ultimate ssb rsa3072/C9597E8F28359AE3 created: 2018-01-01 expires: never usage: E [ultimate] (1). User <attesting_user@example.com>
gpg> key C9597E8F28359AE3 gpg> revkey
To update the modified PGP key on the attestor:
$ gcloud container binauthz attestors public-keys update \ ${FINGERPRINT} \ --attestor=my_attestor \ --pgp-public-key-file=public_key1_updated.pgp
To remove this new key from the attestor:
$ gcloud container binauthz attestors public-keys remove \ ${FINGERPRINT} \ --attestor my_attestor
These flags are available to all commands: --help.
Run $ gcloud help for details.
COMMAND is one of the following:
- add
Add a public key to an Attestor.
- remove
Remove a public key from an Attestor.
- update
Update a public key on an Attestor.
PGP is an encryption standard used by Binary Authorization to create and verify attestations. A PGP identity is encapsulated by a "key" which can be used to sign arbitrary data and/or verify signatures to be valid. As with other asymmetric key cryptosystems, PGP keys have a "public" part and a "private" part.
An important feature of PGP keys is that they are hierarchical: Every "PGP key" is composed of a "primary" key pair and zero or more "subkey" pairs certified by the primary. These key pairs are collectively known as the "PGP key." The "public" part of this PGP key contains the public keys of all the constituent keys as well as all associated metadata (e.g. an email address). And, as might be expected, the "private" part of the PGP key contains all constituent private keys and metadata.
One property of subkeys is that they may be marked as "revoked" if they are compromised or otherwise need to be retired. This does not remove the subkey from the PGP key but simply adds metadata indicating this revocation. The primary key pair cannot be revoked by this same mechanism.
The most common key structure is to have the primary key pair only used to certify subkey pairs while the subkeys are used to encrypt and sign as necessary. This allows the PGP key as a whole to act as a durable identity even if an encryption key is used improperly or a signing key is compromised.
Authorities hold a set of PGP public keys that are used to verify attestations.
- —
These must be submitted in ASCII-armored format. With GPG, this is accomplished by adding the --armor flag to the export command.
If any of the public keys held by an attestor verify a given attestation, then the attestor considers that attestation to be valid (see gcloud alpha container binauthz attestations create help for more details).
- —
As a result, the compromise of any constituent private key means that the attestor is at risk. The compromised subkey should be revoked and the PGP key re-uploaded or removed from the attestor.
These variants are also available:
$ gcloud alpha container binauthz attestors public-keys
$ gcloud beta container binauthz attestors public-keys