age-plugin-yubikey VS Android-Password-S

_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.

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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.

There is no "database", it's just a bunch of GPG encrypted files synced with git.

For Android there is https://github.com/android-password-store/Android-Password-S....

For Windows the only thing (Pass4Win) i found is unmaintained.

See https://www.passwordstore.org/#other

These are the types of applications that I really love. It stores the data in a cloud service that already has enough free capacity for say a notes app. It's like how we can store pass(1) passwords on a git repository (Sync it with Github) and use that as the destination of Android Password Store[1], and you have a easy password manager.

[1] https://github.com/android-password-store/Android-Password-S...

Since I store most of my passwords using https://www.passwordstore.org/, I have used mobile with https://github.com/android-password-store/Android-Password-S.... I'm happy enough with it. Sucks for getting anything into consoles, for obvious reasons.

That's the exact setup I use on my main phone. There's also https://github.com/android-password-store/Android-Password-S..., which I use on throwaway phones.

I moved to pass cli (on i3 with a simple rofi selector) and the FOSS android app https://github.com/android-password-store/Android-Password-S... synced over Syncthing and I never look back

For encrypted secrets in git I'd suggest looking at sops and password store:

https://github.com/mozilla/sops

https://github.com/android-password-store/Android-Password-S...

Both are extremely useful secrets oriented git tools with support for things like PGP encryption. Both will encrypt with multiple keys too, making sharing relatively easy. The android pass app even manages SSH keys for pushing and pulling. There may be good inspiration in those repos, or even code you can borrow.

Also, thanks so much for making this: it is elegant and lovely. Keep it up!

In addition, plasma-pass, qtpass, android password store (https://github.com/android-password-store/Android-Password-S...) are nice as well. Throw in a NFC Yubikey and OpenKeychain on android, then you can lock them with hardware keys. Since pass uses git, syncing can be done to a private repo on your home network or even just a cheap usb stick.

Oh dammit. I have stopped using Gopass and started rewriting pass just for that reason - missing AGE encryption. At least I have learned something new and I feel better while my fuzzy finder UI instead of their TUI. However, big kudos to Gopass team for awesome work and really useful tool.

Before I start working on next project... Do you recognize any mobile app, which could replace PasswordStore.app for Android but with AGE support?

[0]: https://github.com/android-password-store/Android-Password-S...

I'm thinking about adding encrypted file support to my pass wrapper, p, but I've not really found a good argument to support breaking mobile apps (such as https://github.com/android-password-store/Android-Password-S...).

You'd have to manually look up the entries in a lookup table to resolve obfuscated names back to readable names... Or upstream support for whatever format is devised. I dunno.