Compact JWT

Json Web Tokens (JWT) are a popular method for creating signed transparent tokens that can be verified by clients and servers. They are enshrined in standards like OpenID Connect which causes them to be a widespread and required component of many modern web authentication system.

JWT and Json Web Signature (JWS) however have a long track record of handling issues, which have led to security issues. This library will not be a complete implementation of JWT/JWS, instead focusing on a minimal subset that can be secured and audited for correctness more closely within a limited set of use cases.

When should I use this library?

If you wish to create ECDSA signed JWT tokens, or verify ECDSA signed JWT tokens, this library is for you.

If you are implementing OIDC as a relying party or authorisation server, this library is for you.

If you want to use HMAC signatures, have a full JWS implementation, or have the non-compact (JSON) serialisation support, this library is probably not what you want.

Why another JWT library?

There are already many other libraries for JWT on crates.io however they each have a limitation or design that conflicts with the project goals in Kanidm. Examples are:

• Ring as the sole cryptographic provider - we need to use OpenSSL
• Only supporting RSA - We want to use ECDSA/ED25519
• Full JWS implementation - As mentioned, JWS has a number of sharp edges like alg=none

As a result, nothing "fit" what we wanted, so we are making another library.