Hosting a Web Key Directory (without dynamic WKS)

Ideally a Web Key Directory will be created and maintained through a Web Key Service but organisations or individuals may want to just host a Web Key Directory without a Web Key Service. Using a flat file-structure that needs re-creating if a pubkey changes:

Requirements

• A web server that provides https with a trusted certificate.

Using gpg-wks-client from newer GnuPG (upcoming with GnuPG v>=2.2.12)

GnuPG 2.2.12 has an improved gpg-wks-client tool which can be used to create a local file structure.

Documentation and Gpg4win release pending, compare https://dev.gnupg.org/T4268 .

Method with elder GnuPG version

• A client machine with python and pyme installed (debian package python-pyme)
• The script: generate-openpgpkey-hu (in the Mercurial repository "wkd-tools")

There is an alternative implementation using Python 3, and python-gnupg instead of python-pyme available at https://gitlab.com/Martin_/generate-openpgpkey-hu-3/

Usage

You can either export all the keys in your keyring which belong to a domain or provide an explicit keyring containing the keys you want to publish.

The call:

    ./generate-openpgpkey-hu example.com hu

Will create a directory called hu containing all the keys with @example.com mail addresses.

If there are multiple valid keys for a user in your keyring this command will error out. In that case you can prepare a keyring with only the keys you want to publish.

e.g.:

    gpg --export 94A5C9A03C2FE5CA3B095D8E1FDF723CF462B6B1 | \
    gpg --no-default-keyring --keyring ./wkd-keyring.gpg --import

And then provide that keyring to generate-openpgpkey-hu:

    ./generate-openpgpkey-hu example.com hu wkd-keyring.gpg

Publishing

The hu directory has to be published on your server as https://example.com/.well-known/openpgpkey/hu/

On your server create the according directory and set the permissions according to your system. Make sure that there is no automatic directory listing for .well-known/openpgpkey/hu/.

This example Makefile automates the hu directory generation and publishing (using the python script method as documented above). Edit the variables at the top of the makefile to your RSYNC_TARGET The KEYRING variable is optional and can be empty.

Starting with draft 05 the OpenPGP Web Key Directory specification requires that a policy file https://example.com/.well-known/openpgpkey/policy is available. It can be an empty file, which fits well here, because it is only relevant for the update protocol anyway.

A WKD Checker should be implemented to verify the functionality of the WKD.