Project:Gentoo-keys/Generating GLEP 63 based OpenPGP keys

General info
In this guide we are going to show you how to create a GLEP 63 based OpenPGP Key using gkey-gen tool which is the official way of managing OpenPGP keys in the Gentoo Infrastructure.

OpenPGP
OpenPGP is one of the most widely used cryptographic standards in the world. The OpenPGP standard was originally derived from PGP (Pretty Good Privacy), first created by Phil Zimmermann in 1991, and is now maintained by the OpenPGP Working Group of the Internet Engineering Task Force. One of the most used open source implementations of the OpenPGP standard is the GNU Privacy Guard (GnuPG).

The OpenPGP standard is a hybrid scheme utilizing both asymmetrical and symmetrical cryptography to establish the cryptosystem. The asymmetrical components are used to establish a nPKI (Public Key Infrastructure) ad when mentioning keys in this document, it is a reference to the asymmetrical components. It is a hybrid system when used for data encryption, as the data itself is encrypted symmetrically using a random session key, which is afterwards encrypted individually using the asymmetrical encryption keys of each recipient.

OpenPGP keys (i.e. asymmetrical) normally consists of a primary key used for Certification and Signing and a subkey capable of Encryption. This is often extended to using a primary key for Certification purposes only, and separate subkeys for Signing and Encryption. Such a scheme allows for the primary key to be stored offline, while the subkeys are used for day-to-day use.

When generating a new User ID, a new subkey, creating a certification (signature) of another key, or performing revocation procedures, the primary key will have to be used, and as such these operations are normally conducted on a more secure system. As certifications by other users are tied to the primary key, as components structured below the User ID and User Attributte, this allows for key-rotation without losing existing certificates of the key, e.g. in the event of a key compromise due to loss of a device.

GLEP 63
GLEP 63 is a proposal accepted by the Gentoo Council which provides both a minimum requirement and a recommended set of OpenPGP key management policies for the use of GnuPG  by Gentoo Linux developers. It is intended to provide a basis for future improvements such as consistent ebuild or package signing and the possibility of verification of integrity by end users.

Gentoo Keys
Gentoo Keys is a Python based project that aims to manage the OpenPGP keys used for validation on users and Gentoo’s infrastructure servers.

Installation
The tool that is used to generate GLEP63 openPGP key is. To install it please run:

Post generation phase
After the new key is created the next thing you should do is to generate a revocation certificate. If your lose access to your primary key (either because it gets lost or you lose your passphrase) the revocation certificate will be your only way to mark this key as no longer being valid. Similarly if you have reason to believe your primary key in any way has been compromised it should be revoked.

Generating an encryption subkey (Optional)
The default Gentoo Keys template generates a Certification-only primary key with a dedicated Signature subkey. If you want to use this key for Encryption purposes you will have to generate an Encryption capable subkey at this stage using the following interactive command:

which brings up a shell to work in. Additional subkeys are added using the addkey command and following the instructions.

Backup
You should back up your primary key in a safe location, and want to consider also printing a copy and store in a bank vault or similar that can later be typed in manually or recovered using an OCR scanner. In order to minimize the overhead of such a recovery David Shaw’s utility paperkey (available in the main Portage tree as app-crypt/paperkey) can be used.

Export the secret subkeys
After the key is generated, we need to back it up somewhere safe, but first we need to export the secret subkeys that are to be used on a regular basis.

Publishing the public key
To export the public key to a file use the command

Once you’re satisfied with the newly generated key is configured as you want it, the key should be published to an operational keyserver pool using: