Documentation bug in /README.md #encrypting-to-a-github-user

[ChristopherA]

Environment

• OS: n/a
• age version: n/a

What were you trying to do

Get SSH keys from GitHub to use with age.

What happened

Your home page at https://github.com/FiloSottile/age#encrypting-to-a-github-user suggests:

$ curl https://github.com/benjojo.keys | age -R - example.jpg > example.jpg.age

However, the key at GitHub.com/username.keys is a list auth keys (in my case, for instance, it is a different auth keys for each of my development computers). So this will not work properly if you have more than one.

Separately, SSH best practices is to keep auth keys separate from signing keys, so GitHub now supports the ability to keep those keys separate and makes them publicly available https://api.github.com/users/<username>/ssh_signing_keys, however, it is not well documented, and it is in a JSON array rather than a list. But it is useful.

% curl https://api.github.com/users/ChristopherA/ssh_signing_keys
[
  {
    "id": 184891,
    "key": "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAINTazxjqxsdh3Sv/7fxSTgr3qlCVByYoGDHHe428Fubp",
    "title": "eurynome.local/sign_id_25519_christophera@github.com",
    "created_at": "2023-10-26T06:28:34.882Z"
  },
  {
    "id": 219925,
    "key": "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIMU0/lvWurXvUcrvYNgfb02Ska0qpwC/yv22dvDIxxzh",
    "title": "kymindis.local/sign_id_ed25519_christophera@github 2024-01-04",
    "created_at": "2024-01-04T20:13:55.503Z"
  }
]
% 

See also: github/docs#28577 (comment) & dolmen/github-keygen#54 (comment)

p.s. One of my goals this year is to write up some improved best practices for creation and protection of SSH keys, and their use in GitHub and for file signing. I'll have a zsh script that should be easily adaptable for use with age.

[Martin-Buchholz]

So this will not work properly if you have more than one (ssh key).

Why do you say that? The -R flag accepts a list of recipients, and any of the corresponding private keys can be used to decrypt. Which seems like excellent default behavior.