JWT-specific minutae: the dreaded `alg:none` option

[bumblefudge]

I see that alg is a required header field, but no constraint on the value of that prop. Are un-encrypted JWTs allowed? I often hear of alg:none referred to as a category of security exploits, so if you're ASSUMING encrypted JWTs probably best to explicitly ban unencrypted ones before all kinds of attack vectors creep in that open door :D

[matheus23]

It's kind of implicit, but no, alg:none is not allowed. We could/should clarify this I think.

The first sentence in the JWT structure section mentions the format of "header, payload and signature". We could consider adding a subsection "3.3 Signature".

We could also consider adding a subsection to "6. Validation", talking about the requirement for signature verification.

FWIW, as far as I know all UCAN implementations today require a signature to be present and allow only a small subset of alg.

[gobengo]

Are un-encrypted JWTs allowed?

I think you mean unsigned?

But yes +1 to adding normative language explicitly saying at least

alg MUST not be none

[expede]

Added to 0.10!

[expede]

Closed by #132