age-plugin-yubikey VS pass-import

_o/ hi all, age author here!

The OP link is the spec, here's a few other things you might find interesting

- the Go reference implementation https://age-encryption.org

- the Go library docs https://pkg.go.dev/filippo.io/age

- the CLI man page https://filippo.io/age/age.1

- an interoperable Rust implementation by @str4d https://github.com/str4d/rage

- a YubiKey plugin by @str4d https://github.com/str4d/age-plugin-yubikey

- the draft plugin protocol specification (which we should really merge) https://github.com/C2SP/C2SP/pull/5/files?short_path=07bf8cc...

- a Windows GUI by @spieglt https://github.com/spieglt/winage

- a discussion of the authentication properties of age https://words.filippo.io/dispatches/age-authentication/

- a discussion of a potential post-quantum plugin https://words.filippo.io/dispatches/post-quantum-age/

- a password-store fork that uses age instead of gpg https://github.com/FiloSottile/passage (see also: how I use it with a YubiKey https://words.filippo.io/dispatches/passage/)

I am using the yubikey plug-in for age (https://github.com/str4d/age-plugin-yubikey). It creates a private key and writes it to one of the retired PIV slot. What I want to do is to write the same private key to two different Yubikeys.

So with age I can also just use my ssh public key to encrypt and my ssh private key to decrypt my files. If I want to get fancy, I can use something like https://github.com/str4d/age-plugin-yubikey to provide the key material for my age operations (which should compose with age.el quite well also, i.e. you can have every decrypt operation have a touch requirement in Emacs that way).

> A good feature of PIV applet of Yubikey 5 is that it stores 24 keys.

Note that not all 24 of those keys are suitable for age usage. The 4 main keys have specific usage definitions in the PIV specification that mean hardware tokens alter how those key slots behave. Only one of them (the KeyManagement slot) has a definition that allows encryption, and even that I was somewhat suspicious of overlapping with, as I couldn't predict how those existing keys were being used, and didn't want to support every possible key type that might be in that slot (which users likely wouldn't be able to alter).

age-plugin-yubikey avoids this complexity by only interacting with the 20 "retired" slots, which have no constraining definitions. (I am considering adding restricted support for the KeyManagement slot specifically for CAC card users who aren't allowed to add new keys to their cards [0], but this would be behind a default-off feature flag to keep the primary UX simple.)

[0] https://github.com/str4d/age-plugin-yubikey/issues/62

We designed the plugin protocol (https://hackmd.io/@str4d/age-plugin-spec) and generally the age recipient/identity structure specifically to enable the use of hardware or remote keys!

For example, https://github.com/str4d/age-plugin-yubikey makes it very easy to use PIV tokens, including YubiKeys, with age. (Well, for now with rage, since plugin support is coming in age v1.1.0.)

I argue against password-protecting keys by default because, unlike using hardware tokens, it doesn't protect against many threat models.

Hardware? I assume if someone was concerned about key access they wouldn't want keys on their filesystem at all but move them into an HSM instead. Since age identities can come from standard input I assume it'd be feasible to put together a workflow there coming from one of the various cli utilities for interacting with keys. There is already a YubiKey specific age plugin [0] getting worked on as well. Currently in beta but looks interesting. Hopefully that will continue to expand to cover other common options. HSM support is pretty important for a modern encryption utility IMO but unfortunately the landscape is pretty all over the place too, so makes sense to just leave it to plugins or as part of a unix flow.

----

0: https://github.com/str4d/age-plugin-yubikey

age also has a notion of plugins, one of which is age-plugin-yubikey (written in Rust, there is also yubage written in Go) which allows you to create an age identity whose private key is stored via PIV.

> I always tell these people to just sign up for a password manager and they always resist and say no. I must be missing something obvious.

Maybe they don't want to be relying on a random third-party for all their passwords?

Rather than getting them to sign up for a password manager, what about getting them to install a password manager? I use https://www.passwordstore.org/ - it encrypts your passwords with GPG, and shares the storage via a Git repository for synchronisation between different machines.

That way you can delegate the password handling to another program, e.g. a password manager like pass(1) (https://www.passwordstore.org/) or some interactive graphical prompt.

I want to move to something compatible with https://www.passwordstore.org/ - an open standard for keeping your passwords in a folder encrypted with OpenPGP.

The problem is that I'm nervous to give an unknown Android app and browser plugin total control of my passwords and access to my github account when I don't have time to review it's code properly. I have a bit more trust ing the command line tools, but I'd like to be sure that more people are looking at the code before I trust my life to it.

> Create a system or pattern based on url or brand and mentally hash it into a password.

Doesn't sound very secure. Also when you realize that you anyway have to trust cryptography, I believe it starts making a lot of sense to have an actual cryptographic key and encrypt it with one good random password you learn by heart.

I use pass https://www.passwordstore.org/, which encrypts my passwords with my GPG key, which comes from my Yubikey, which I unlock with a password. That means that I only need to remember one password, and it feels a lot more secure than your pattern based on url or brand.

i use pass and keep my database on a local git repo. it encrypts your passwords with gpg and is a really simple command line program

If you want portability and simplicity, there's a project called simply pass that uses standard *nix utilities (and git, I believe) to manage passwords from CLI.

0. Pass is just text files encrypted with gpg. I needed just one password on one work computer, where I had my gpg key, but not all my passwords. Decrypted the file and that was it.

1. There are plugins and web clients: https://www.passwordstore.org/#extensions

I've been incredibly happy with https://www.passwordstore.org/ for years. The data store is a file hierarchy, with the files themselves encrypted with GPG. Sync is via git. TOTP support with a plugin.