biscuit-rust VS cookie-session

> We have a post on this coming soon! The short version is that Polar is a logic language based on Prolog/Datalog/miniKanren. And logic languages are a particularly good fit for representing the branching conditional logic you often see in authorization configurations.

Ha, I've been playing around with Biscuits (https://www.biscuitsec.org/) and was writing up a blog post on using them in a git forge. When I saw the Polar data units described as "facts" and read your end to end example (https://www.osohq.com/docs/tutorials/end-to-end-example) I thought "Oh this looks very similar". I will say - I do like how Polar seems to type stuff and provide some concepts that Biscuits force you to build out on your own, that's pretty neat.

What is the proof of identity in Polar? Is it something like a token in Biscuits? I'm curious if you can do things like add caveats to reduce what the token is capable of as it gets handed off to different systems. I consider that one of the "killer use cases" of biscuits.

I ported biscuit-java to Kotlin for an internal project. In the course of doing so, I went from a naive superfan to a somewhat grizzled advocate. Here's my high level summary:

Why Biscuit instead of JWTs?

tl;dr, Biscuit (and Macaroons) can attenuate, JWTs can't.

Read: https://fly.io/blog/api-tokens-a-tedious-survey/

What does this mean? Let's say you're given a token to access System A and B whenever and however you want. You can create a new token from your token (attenuate) that only gives access to System A for the next 5 minutes.

Basically: attenuation gives a capability system.

Why Biscuit instead of Macaroons

tl;dr Biscuits are easier to understand (and implement) than Macaroons.

Watch: https://www.youtube.com/watch?v=MZFv62qz8R

Macaroons are clunky and hard to work with in practice. That's probably not a feature you want in your choice of token technology.

Biscuits contain simple facts and clear policies written in Datalog.

Why NOT Biscuits

Immaturity.

- AFAIK there is no compliance suite for all the Biscuit libraries linked https://www.biscuitsec.org/; and as such, unsurprisingly, there are corner case incompatibilities, especially in the authorization language parsers and Datalog expressions/operators.

- The Datalog runtime limits are user-defined. What is the maximum number of facts, application iterations, or even timeouts? That's up to you.

- Biscuit v2 (v3-4 in the proto) is the Official Latest Version. Some of the libraries support the older versions to varying degrees.. and the way that backwards compatibility is implemented gave me pause.

- Whole sections of the specification are `TODO`.

- The Datalog data types are bounded by the underlying protobuf definitions; and the libraries use the language native data types. There are casts and undefined behaviour at the extremes.

- Many of the libraries do little things like calling the equivalent of `Time.now()` internally. IMHO this sort thing should be stateless.

- There's heaps of tests, which is great! But, I didn't see any fuzz or property tests, which is less great.

Summary

Biscuits neatly package several simple and solid technologies: datalog, ed25519, protobufs. Once the ecosystem is mature, it'll be incredible.

> The point of JWT vs opaque tokens is that you can just inspect the token itself to derive permissions without hitting any sessions in DB, right?

As I understand it, de-centralized verification isn't a necessary characteristic of a JWT. There are token constructions that make that a priority, however[0].

[0]: https://www.biscuitsec.org/

a C compatible library thanks to cargo-c

I like the Datalog-based policy language used in Biscuits.

https://www.biscuitsec.org/

Has anyone tried https://www.biscuitsec.org/ ?

I haven't seen it much discussed, and seems to solve a lot of issues from JWT

The lack of logout and XSS are problems, but I ran into a couple apps that completely forgot to expire sessions due to lacking framework support. In nodejs's cookie-session and @google-cloud/connect-firestore sessions never expire. This issue impacts downstream software including, awkwardly enough, Google's Passkey demo apps. There isn't interest in fixing this.

Make sure your app is actually using a JWT framework, not a lesser version, and implements basic security practices.

[1] https://github.com/expressjs/cookie-session

[2] https://github.com/googleapis/nodejs-firestore-session

Side note: a JWT in an HttpOnly cookie, which is what some people advocate, is still a cookie-based session. Using a library like cookie-session would already give you the ability to have a signature-verified JSON payload, just like using a JWT would.

Frameworks usually sign cookies by default, or at least offer an option to do so. Some (like Ruby on Rails) can encrypt them for you too. There's nothing really stopping you from storing data in them just like you would a JWT. In fact, frameworks and session libraries often use this cookie storage by default (even in the Node ecosystem, e.g: koa-session, express cookie-session), since an in-memory store can grow to an arbitrary size. Of course, you can also just store a JWT in a cookie, which has the advantage of being standardized in terms of claims and signing algorithms etc.