Asymmetric cryptography solves problems of statelessness: i.e. encrypt your sensitive|read-only data with your public key, decrypt it with your private key, beep boop, you can now use your client as a database. JWTs are a whole other unnecessary lasagne of complexity – not good complexity but random complexity, like the human appendix – which invites bugs and adds nothing above the former in most implementations. (Hell, my current company generates JWTs and then uses them as plain old 'random' keys to look up the session data in a database. It's hilarious but also awful.)

Well, asymmetric cryptography is not even needed in the most common case, i.e. when you are using the client as a database. Symmetric crypto is enough, because it's your server that both encrypts/signs and decrypts/verifies. Asymmetric crypto may be strictly needed only if the sender and the recipient are different. And there is still an issue that the malicious client can return old and outdated but validly signed data - which you can't solve without either a server-side database or accepting old data up to a certain limit.

Yeah, that's true, actually. As best I recall, I just meant that that is what people use JWT for regardless, and I wanted to convey that the only part doing the useful work there is the 'asymmetric crypto' part. I didn't want to get into the territory of providing alternative suggestions, only breaking down what is useful about JWTs when used for that purpose.

As for old and outdated data, I should think that's easily solved by having a 'created' and 'modified' stamp in the encrypted data, much like you have on an inode.

> Most companies don’t have these problems

Can anyone cite a single real world example of a fully stateless system being run for the purpose of business? I ask this every time JWTs come up and no one can answer it.

As soon as you tap the database on a request for any reason, whether it's for authorization or anything else, you might as well kiss JWTs goodbye.

Then again, just don't use them anyway, because they have no benefit. Zero. Disagree? Prove it. I'm sure there's some infinitesimally small benefit if you could measure it, but the reality is that JWTs are saving you from an operation that databases and computers themselves are designed to be extremely good at.

Don't use JWTs. They're academic flim-flam being used to sell services like Auth0.

They can be helpful if you have services that need to call other services on behalf of a user request.

For instance, user A calls Product service for Product information but that response also includes Recommended Products and Advertisements from those two services. Product service can pass the JWT from the client to Recommended Products and Advertisements which removes the need to establish trust between those internal services (since authentication and authorization info are just passed around from what the client provided).

You can also use them in federated auth schemes where the issuing system is separate from the recipient. I think the use cases are pretty similar to SAML for this type of system but with a smaller "auth token" size.

Just because you're accessing a database on a request doesn't mean you're accessing the database that stores the authorization and authentication info.

The problematic word is "THE" database. The subsystem that you hit can be not stateless, but can use a separate database that doesn't contain authentication data.

I can only provide verification of the counter example.

Having worked on some VERY large web services, the session was tracked on the back end and instantly and trivially revocable.