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.
Json Web Encryption (JWE) is an occasionally used method for sending secrets to a recipient or to create opaque tokens for services.
JWE, 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 JWE/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.
If you are:
- creating ECDSA signed JWT tokens, or verify ECDSA signed JWT tokens
- implementing OIDC as a relying party or authorisation server
- wanting to use HMAC signatures for transparent json data
- needing a minimal secure JWS implementation
- using TPM bound keys for signing JWTs
- creating opaque encrypted tokens protected with AES-128-GCM
- receiving or sending encrypted data to an ECDSA key
Then this library is for you
If you need non-compact JWS, or other complex use cases, this library is not for you.
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:
- Incorrect Implementations - There are a number of JWT libraries in Rust that are incorrect to the RFC or do not have RFC vector tests
- Ring as the sole cryptographic provider - we need to use OpenSSL
- Only supporting RSA/Weak cryptographic algos - We want to use ECDSA
- Full JWS implementation - As mentioned, JWS has a number of sharp edges like alg=none
- No library supports pkcs11 or TPMS - We aim to allow hardware security modules to store private keys
As a result, nothing "fit" what we wanted, so we are making another library.